SuSE Openexchange is pretty nifty, though I'm no big fan of SuSE Linux.
But for an admin that doesn't wanna get his hands dirty with config files and such, Yast isn't a bad tool, so SuSE might be a good choice for you.
Redhat is a bit more of a "traditional" UNIX, it's graphical tools are pretty simple but not nearly as capable as Yast, on the other hand, I personally like it alot more than SuSE because it doesn't make the same effort to be "Windows like".
Anyway, as has been pointed out, there are free evals available, just try'em out 🙂