I've tried Mandrake 8.2 and RedHat 7.3...they each have problems. Mandrake 8.2 seems to be a bit buggy and it is definitely slow (even for Mandrake), as it ran in an extremely lethargic manner on my Athlon 1.4; RedHat 7.3's installer is a bit buggy (not excusable), so if you're looking for the full install, it may not be your best option. As a matter of fact, 7.3 is buggy enough in places that RedHat has already release the 7.4 beta for testing.
I've just done an FTP install of SuSe 8.0 (mostly because I don't have to recompile my kernel to get my Audigy to work) and I actually do like it; I'm not as familiar with it as RedHat, so I'm having to find things all over again, but no distro is perfect (or exactly like another). However, if you're not at all familiar with 'nix, I wouldn't recommend an FTP install.
Overall, as a noob, I would say that you should probably go with Mandrake, but I hope that you have a really fast machine so that it doesn't act like XP on a 486...
By the way, guys, the default desktops for KDE and Gnome on the new SuSe are extremely pug-fugly...I have no idea what they're thinking.