C2 had some major hardware support issues (firewire, they have to fix that at the kernel level) but the final release of C2 did not strike me as very buggy (with the exception of X.org and language switching).
Just when we were feeling comfortable with core2 and RHEL, they go and mess it all up again...
If youre using RHEL and its under support why go to C3, for that matter if youre that happy with C2 why go to C3. If three test releases is not enough stick around on C2 its not going to legacy for more than four months and even after that there is full support through the fedora legacy project..