As far as personal opinion...
My personal opinion on Windows:
It was based on an extremely buggy operating system (DOS)... and remains one of the buggiest operating systems out there. It takes up too much HDD space that could be used by the user. It takes up way too much RAM just to remain running properly. Each new release requires more and more system resources, while Linux and Mac updates (typically) either run the same or faster than their previous versions. The audio system is somewhat primitive and lacks a few features in comparison to the other two operating systems. The only thing good about this OS, in my opinion, is the amount of useful applications. Most applications have Windows versions and quite a few are Windows-only. And the general quality level of these applications is usually higher. However, there's usually a price tag for the more-useful of apps.
My opinion on Mac OS X:
Stable, uniform, and easy to use. I don't have nearly as many negatives against this operating system as I do with Windows. And I actually have a few positives about this one. The lack of customization is both a benefit and a downfall. All Macs will have the same GUI and layout. If you know how to use one mac, you know how to use them all. However, customization is a good thing. What happens if you get fed-up with the "dock"? You can't get rid of it. You can't replace it. You're stuck with it. Unrelated to customization, I like the Mac's global-menu system. It brings a nice set of unity between different applications, even though this sense of unity doesn't have any real meaning or use. Macintosh PC's are pretty eye-candy.
My opinion on Linux:
Everybody knows linux is a beast of an operating system

. There are few negative issues, as far as I can see. There is no quality-control with applications, although there are some really good open-source apps that demolish their proprietary counterparts (GIMP, LibreOffice, gEDA, etc.)... linux is based on the open-source concept, so most linux-based apps are open-source and community-driven, as well. The biggest strength of the operating systems can also be one of the biggest annoyances-- the customization. I've been constantly switching between Gnome3, Gnome2, MATE, Cinnamon, XFCE, LXDE, KDE, and OpenBox desktop environments and window managers. I've stuck on Cinnamon for a while, but now I'm itching to get back to XFCE. There are simply too many options with so many great features, that it's difficult to make a solid decision. Also, while most hardware is supported, there are a few incompatibilities. For example, my Focusrite Saffire 6 doesn't work in linux...no driver. Other than those minor downsides, this is my favorite operating system ever.
Just my personal opinion
