Changing C libraries is no trivial matter. The good news is that I've not discovered any C library-related problems with any of the software that comes with RH5. The bad news is that any software brought in from elsewhere might not work. If compiled under RH4.2, it runs fine under RH5. Recompiling under RH5 solves the problem.
Installation is outstanding.
You can go from zero to a bash prompt in an xterm window in 15 minutes. This was my second try with Debian. Beyond this, however, I was not terribly impressed. Worse, it had to ask twice during the process where it could find the CD-ROM drive. It didn't remember the answer from the first time it asked.