An anecdote about OS X vs Windows 7:
I have a three year old MacBook Pro 17”, running, of course, OS X. I run Windows 7 in a Parallels virtual machine on this computer, for those times I’m doing CAD work; Solid Edge is the only program I regularly use for which I need Windows.
About a week ago, Windows 7 became unstable, for no particular reason that I could see; after a few odd symptoms, it did something that filled up the (virtual) hard drive partition, after which it became non bootable.
Fortunately, I regularly do a file-by-file backup to an external drive. I deleted the bad virtual machine and copied my backed up 35 GB virtual machine back in it’s place; and I’m up and running again in 45 minutes.
I never store my work on the virtual machine. It is a bare Windows 7 installation, with Solid Edge and a couple of other minor programs installed on it. It works fine most of the time. The fact that my working files are on my MacBook’s primary hard drive, which is automatically backed up by Time Machine; and the fact that I had a separate file-by-file backup on another USB drive; saved me a LOT of time getting back up and running.
Post mortem: I don’t trust Windows; any version. The system went unstable and less than five minutes later was unbootable; and that is not the first time Windows has done that to me. However, it is the first time while running on a virtual machine, though, and this is the quickest recovery I’ve ever had – because I had the whole thing backed up as a single file.
OS X? I’ve been running it for around 3 1/2 years now, and have had zero down time.
Draw your own conclusions. As for me, I’m sticking with OS X. Reliable like an anvil, fast as a rocket.