I used to use mandrake, but switched to redhat for two reasons: 1) my company webserver is Red Hat Enterprise and 2) everything linux seems to be tested on Red Hat.
I switch to fedora in the middle of the core 2 test vesrsions.
Mandrake is better in some areas, but fedora and RHE seem more stable, not to mention the support.
At least you can find help all over the net for fedora, unlike mandrake...
http://distrowatch.com/ they don't count users, but it does count the number of people looking and what they are looking for...
I also am back in school. Just aced a Sun Solaris class. Next year I will be linux, MS, and Solaris certified. I will cover all the big guys... Though I dislike windows and lean towards the *nix side of things....
I own a technology integration company and need to know more than most people...
If you are new to linux I would suggest mandrake. If you want what appears to be a standard for linux get fedora or RHE.