Some years ago, I've heard people saying that the OSX and Linux were better than Windows, I also remember of reading something that said the Solaris operating system didn't fragment their files and that the Linux file system was almost in the same step but none of these claims seemed to have basis or references.

I got two questions:

1. When comparing operating systems, what are the main points for comparison?
2. How's the comparison between the main operating systems today?