I've been playing around quite a bit with Fedora Core recently, the successor to the non-enterprise versions of RedHat Linux -- RedHat 9.1, if you want.
Like RedHat 9, Fedora is an excellent desktop environment, most notably including OpenOffice 1.1 (which is excellent) and Mozilla 1.4.1; gaim is a good unified instant messaging client. Of course, mathematicians' and Unix users' traditional favorites like TeX, xfig, gnuplot, and friends are also included. Like RedHat9, Fedora is better on the desktop than the latest stable Debian (which starts showing its age), offering more mature versions of many of the productivity applications, and (finally!) offering nice-looking font display under X11.
There are a couple rough edges, though, in particular when it comes to manageability: Upgrades and package managing in general are far less mature (and far less scriptable) than what Debian has been offering for several years now. For instance, there's still seems to be no easy way for a user to tell a rather bare-bone system "give me GNOME" -- you have the choice between installing RPMs "by hand" and using a GUI software installation tool that gets the installed packages wong and complains about dependencies that have long been fulfilled. Even the dreaded dselect was much better than that.
Also, an upgrade from a rh9 system with postfix installed may quite well install a sendmail package along with the postfix upgrade; it's pure luck whether or not the links for, say, /usr/sbin/sendmail are correct or not after you remove sendmail again. Once again, properly fixing alternate links is something Debian has been doing correctly for years now.
When upgrading large numbers of computers (possibly from even older RedHat versions, with different sets of packages installed), rough edges like this one greatly reduce the benefit you can get from an NFS-based kickstart installation (or upgrade) -- in particular since package selections can't be comfortably adjusted from kickstart files, when upgrading. Ultimately, it's not the theoretical "insert CD, type 'linux ks', walk away", but at times much more work. In such situations, an apt-like mechanism that's integrated with the installation system would be worth a lot.
Random additional notes: Make sure you remove any special nvidia driver packages before upgrading from old RedHats, since these packages confuse the new XFree86; don't let the hpoj package near any HP OfficeJet devices that connect to an SMP machine's USB port (this combination quickly leads to reproducible lockups; this seems to be a long-standing issue in the 2.4 series of Linux kernels); don't let pine talk SMTP to postfix's sendmail binary (sendmail -bs hangs in combination with pine; this worked with RH9), instead force it to use TCP/IP to reach the SMTP server that listens on localhost (/etc/pine.conf.fixed is your friend).
