I tried RedHat about 5 or 6 years ago and currently use OpenSUSE 10.0, which I'm a fan of. I've also worked with Ubuntu and while I like the apt-get functionality, I am under the impression that it tries to be too easy for new users and makes some features more complicated. I haven't worked with it enough to be sure of that, but that's just my impression, especially with scanners and the fact that it didn't have the ability to compile software from source until installing make and a compiler. As for Unix I don't usually work with it and only have tried HP-UX which I can't really say much about