I've been with Apple now for two years, and haven't run into any compatibility issues. I'll grant that it takes some hunting to find the software you need to do various tasks, but the programs are there -- and usually they're of a significantly higher caliber than the comparable junk warez you'd find on the likes of Download.com.
To a degree, yes. However, I own "The Sims 2" for PC. If I want the Mac equivalent, even used, it's $30. The PC version used? $4. So I dual boot and run my Windows OS to play my PC copy. That's just a game, though games are the worst offenders.
Another example: Graphics programs. Art, photo and drawing freeware for the Mac is very limited. I own a program called Pixelmator for the Mac, and I paid $59 for it. For the PC, I have PSP XII and for that I paid $59 at the time. Pixelmator compared to PSP XII just cannot compete. It's clunky, non-intuitive, has fewer tools and is slower and underpowered. PSP XII on the other hand gives me almost as much freedom as Photoshop, is fast, easy to use, has alot more refined tools, and is intuitive to use. It is far superior to Pixelmator.
The same can be said for DVD authoring freeware programs. Windows? I can name five right now, all spyware free. Mac? I can name two, and they are rather slow and clunky.
There are many programs for PC that are freeware that cost on a Mac and there is no freeware equivalent, believe me, when it comes to Windows, I am the Master of Freeware. I know where to get it, and what to get. I never have spyware, adware, kludgware or virii. Macs have an okay selection, but it usually isn't as good as it's Windows equivalent. To get better quality for Mac, it usually costs, and not always reasonably priced either.
I love Mac OS X, but I realize it's shortcomings. This is why I dual boot.
J.