Apple Mac OS X vs Microsoft Windows
|Mac OS X||Windows|
Apple Mac OS X and Microsoft Windows are two of the most widely used desktop operating systems. Apple's Mac OS X is more commonly known as just simply: "OS X" and is derived from FreeBSD - it is now being customised and developed by Apple for their own line of PCs, often referred to as "Macs." Windows is developed by Microsoft for any PC (including Apple's). For a comparison between Macs and other PCs, visit Mac vs PC.
OS X and Windows both have a long line of releases in their history. The X in OS X stands for 10, signifying the 10th major release of the Mac operating system. Within the Mac OS X line-up, there have been incremental sub-versions named after felines. Windows began with 1.0, following the numeric system until 3.1, after that Version NT 3.51, NT 4 and Windows 2000 for the enterprise and Windows 95,98 and Millenium Edition for personal uses. Both lines merged again starting from desktop oriented Version Windows XP, followed by Windows Vista, which was followed by Windows 7, Windows 8, Windows 8.1, and Windows 10 (current). Besides there are server-releases named Windows 2003 and 2008, 2012 for enterprise and Windows Home Server 2011 for personal use.
The percentage of the market held by either OS is unclear. According to one source, Windows has a market share of 91.8% compared to OS X with 7.3% .
Also, sales numbers do not necessarily reflect actual usage levels of various operating systems. Most new PCs are purchased with Windows installed, but users may opt to change or upgrade to a different OS. Additionally, some argue that Apple computers have a longer lifespan, which could mean that sales of Apple computers do not accurately reflect their current usage levels compared to Windows computers. However, the market share based on web usage in 2015 is about 91% for Windows compared to 7.4% for OS X. 
"Awesome out of the box" - Mac touts the software that comes bundled with their computers.
|Software Type||Mac OS X||Windows|
|Web Browser||Safari||Microsoft Edge, Internet Explorer|
|Photo Editing||Photos||Photo Viewer/Paint|
|Word Editing||iWork (Pages)||Word 2016 (paid)|
|Spreadsheet software||iWork (Numbers)||Excel 2016 (paid)|
|Presentation software||iWork (Keynote)||PowerPoint 2016 (paid)|
|Media Player||iTunes / QuickTime Player||Windows Media Player, Windows Media Center, Groove Music (Windows 10), Videos (Windows 8)|
|Movie Production||iMovie||Windows Movie Maker|
|Development Tools||Xcode||None by default|
|PDF Viewer||Preview||Reader (Windows 8.1), Microsoft Edge (Windows 10)|
|Calendar||Calendar||Windows Calendar (deprecated)|
|DVD Authoring||iDVD (deprecated)||Windows DVD Maker (in Premium editions)|
|WYSIWYG Website Authoring||iWeb (paid)||None by default|
|Chat||iChat / Messages ,Skype,||Skype (Windows 8.1 and later)|
There are far more software titles available for Windows. However there are generally strong applications available for both platforms for virtually any software area. One exception is gaming software, which is much more prevalent on Windows. OS X tends to have stronger offerings in Music and Video production.
|Software||Mac OS X||Windows|
In order for software to significantly modify Mac OS X, you have to type in your password... A Mac gets much of this out-of-the-box protection from its open source UNIX heritage. The most critical components of Mac OS X are open for review by a worldwide community of security experts.—Apple Inc. , Get a Mac
Apple touts this feature as an advantage over (pre-Vista) Windows: "On a Windows PC, software (both good and evil) can change the system without your even knowing about it." The latest version of Mac OS X added sandboxing to improve protection against malware and trojans, but it cannot protect against malware that a user installs.
Windows Vista recently started to focus more on security by implementing a stricter user-permission policy (called User Account Control, or UAC), but many users feel that the strict policy is more annoying than useful, resulting in some of these users disabling the feature altogether. Windows 7 has partially reduced those policies attempting to blend security with acceptable Windows user experience.
Windows' large market share has made it a target for hackers creating viruses and other malicious software. Some counts place the number of Windows/MS-DOS viruses at over 50,000. It is critical that Windows users diligently run anti-virus programs and keep them up to date.
Infection of Macs running OS X is also common, but there has rarely been a large-scale infection of computers running OS X (but the same goes for OpenBSD, FreeBSD, AIX, HP_UX and Linux et al). The same security measures that secures Mac OS X applies to these operating systems - due to OS X's core security being inherited from unix.
Both Macs and Windows have patches and/or updates provided online by Apple and Microsoft, respectively.
Through one simple button-click change in the System Preferences this can be on or off, to differing degrees. Ever since the release of Mac OS X 10.1 on September 25, 2001 as a 'free update' to version 10.0, Macs can download these automatically or the [owner or administrator] user has the option of accepting these downloads or not: "New software is available for your computer. If you're not ready to install now, you can use the Software Update preference to check for updates later."
In Windows XP, Vista and Windows 7, the user has the option of turning automatic Windows updates on or off. Most major Windows applications install their own update programs which periodically check to see if the particular application is up to date.
People who prefer Mac claim the following:
It just works... all the hardware and software just works, and works well together.—Apple Inc. , http://www.apple.com/getamac/
That’s because a Mac offers absolutely flawless integration of hardware and software. Only with a Mac do you get a system built by the same people who make the OS, the applications, and the computer itself.—Apple Inc. , http://www.apple.com/getamac/works.html
Mac users who have Windows in their past tend to agree on a simple point: The Macintosh operating system and its custom-tailored hardware make for a far more reliable, less trouble-prone environment than Windows. It's difficult to put a price tag on that advantage, but it's the advantage that I find the most compelling.—Scot Finnie , Ding! Mac vs. PC cost analysis, Round II
Independent testing by Consumers Union ConsumerReports.org rated customer tech support highest among OSs - and reduced interferences resulting from 3rd party software conflicts - probably since Apple controls both hardware and software in out-of-the-box purchases raising the quality expectations and user experiences.
"Customer complaints & Issues"—Apple Defects , Apple Defects
New MacBook Pro 15" user had to deal with 7 replacements within 2 months—"The Unofficial Apple Weblog" , Apple's Dwindling Quality
3rd Post- "helped a little bit, but not much... seriously i never thought id want to go back to windows, but its happening!"—Mac Forums , Apple OS X slowing down more than a Windows XP machine
Apple suffers under defects just as many times as other companies due [do] but are given a pass when other companies pay dearly for them. Since it is seen as "cream of the crop" despite not having the best in any category.—CNET Don Reisinger , Is Apple the Only company that can do no wrong?
Operating system upgrades
Latest upgrades: Yosemite 64 bit - Free upgrade from Snow Leopard (10.6.8), or later. Released 2014
Mavericks 64 bit - Free from App Store. Released 2013
Mountain Lion 64 bit - $19.99 download from App Store. Released 2012
Lion 64 bit - $29.99 download from App Store or ordered on a USB stick. Released 2011
SnowLeopard 64 bit - $29 - Upgrade is done in place and typically takes about 45 minutes. Released 2009
SnowLeopard has brought widespread improvements to the Apple computing platform. It is capable of running as a fully 64 bit operating system on computers which support this. Grand Central Dispatch is available to applications for better use of multiple processor cores and OpenCL allows applications to utilize the power of graphic processors for uses outside of graphics. SnowLeopard is also approximately 7GB smaller than Leopard. Several tweaks have also been made to the interface.
Windows 7 Home Premium 32 bit $119.99 - Upgrade from Vista requires no full install, no backup, however it is (unofficially) recommended to perform a clean install because an in-place upgrade leaves a lot to be desired in terms of stability compared to a clean install. This also applies to Mac OS X.
Windows 7 had many of the same kinds of upgrades over it's predecessor as SnowLeopard did. The performance of Windows 7 was improved substantially as a direct response to consumer disappointment over performance issues of Windows Vista. Steve Ballmer confirmed that 'Windows 7 would be a refined version of Windows Vista' while speaking about Windows 7 on October 16, 2008.  There are many who believe that Windows Vista was released prematurely and Windows 7 should have been released as a service pack, rather than a new version of Windows for purchase.
Every other release of Windows is a refinement of the earlier based on kernel version numbers. For example Windows 2000 was 5.0 while Windows XP was 5.1. Vista was 6.0 and 7 was 6.1. Mac OS X has major revisions every few years with many changes under the hood, except for Snow Leopard, which was a "refinement" release. Mac OS X also has minor updates with bug fixes and added features. The version numbers are as follows, 10.x.y, where "x" is the major release and "y" is the minor release. Contrary to popular belief, 10 is NOT the major release number, it is simply part of the operating system's name, which is Mac OS X (a latin letter "10").
Backup / Restore
Mac OS X - TimeMachine - Automatically or manually backs up system as often as you chose as well as reverting the system back to a specific date and time of your choice. Also cloud based storage and backup services are avail for free as well as a paid upgrade for more storage.
Windows 7 - System Restore can restore the computer to an earlier state, and Backup can automatically backup your system
Windows 8 - File History automatically backs up important files
Mac OS X - Disk fragmentation may occur, but less frequently than before because of several improvements. 
Windows - Requires occasional defragmentation with XP or below. Vista and above have defragmentation set to run automatically out of the box.
While Mac OS X does have the benefit of faster startup and shutdown in many cases, as well as higher performance in many other areas, an article by CNET editor Dong Ngo suggests that graphics applications may run faster on Windows 7. . This article describes a test in which benchmarking software was run on the same MacBook Pro both in pure (not virtual) Windows 7 and Mac OS X environments. According to Dong "Windows 7 noticeably outdoes Snow Leopard in the 3D image rendering benchmark." It is also noted on Call of Duty 4 that "Snow Leopard was always 5fps to 7fps slower than Windows 7."-Dong. The other areas of this test confirmed the better general performance of Mac OS X. His conclusion was that Windows 7 is the better choice for gamers. .
Many Linux users prefer Macs over PCs because of the Mac's UNIX architecture. There are many projects (Homebrew, MacPorts, and Fink) focused on compiling popular open source applications for Mac OS X that usually run on Linux.
The kernel of Mac OS X (Darwin, which is responsible for running applications, booting up the computer, and many many other behind the scenes things, and is based off of the BSD kernel), as well as components such as WebKit and CUPS are open source software. The user interface and applications bundled with the system are generally proprietary.
Comparing Apple to Microsoft is almost completely meaningless in this context, because Apple is a company in the hardware business that happens develop and bundle an insanely great—but non-free—OS with their hardware.—Raganwald , Apple is in the hardware business