The only real warnings I'd list about gentoo are these:
**MUST be on high-speed internet connection if you want to enjoy the expeience.
**MUST be able to read and follow instructions well - the instructions on www.gentoo.org
WILL WORK if you pay attention to the 'do this if... but don't if...' parts.
**Gentoo software installations are run off of a Portage system rather than an RPM system, so please do get to know linux before trying gentoo, but don't get hung up on looking for RPMs when you want software. Take some time to read about and understand the portage software handling system as described on www.gentoo.org
BEFORE you dedicate yourself.
**Because of the system-specific build nature, Gentoo is not the best distro if you're planning on building the OS on one system then transferring the hard drive to a new box. Solved by building Gentoo on the new box and transferring settings.
**Like working in a shell/console for system updates rather than point-and-click, as emerge works best via typed commands (I would assume this already if you're using linux for more than email/browsing/word processing).
Major bonuses of gentoo:
**The entire OS and all programs are personally tailored to your hardware and personal preferences, so you have less bloat than most any other OS/distro (no scanner programming for your processor to ignore if you don't have a scanner) and therefore have a very FAST system.
**Updates to entire system (added a scanner) with one 'emerge' command.
**Complete control over installed software (what is/isn't installed and what will the installed software do), and all dependencies are automatically dealt with via emerge.
**Latest versions (or older based on your preference) of everything, and automatic reconfiguration of related software for updates (upgrade KDE and all KDE-dependant software will be updated to respond to the new version)
You'll notice I use Gentoo. I love it. I'm not a programmer at all, but I can follow instructions well, have cable internet, and don't change my video card and processor every 3 weeks. And, not to belittle these forums in ANY way, the Gentoo forums are also amazing - for Gentoo issues.
In response to your RH issues - RH has announced that they will not be supporting their user distros after April (5 months) so they can focus entirely on Enteprise. Looks like you'll be looking for a new distro anyway... if you like easy and capable go Mandrake or SuSE to keep with the RPM software format. If you're looking to grow go Gentoo or Debian/clones.