[Fedora-sparc] RHEL and Fedora compatibility

I also have yet another question and this may be one of the other silly questions, but are CentOS / RHEL rpms compatible with Fedora? As I mentioned, one of the biggest reasons I want to try out Fedora or any Redhat based Distro is primary because of the driver availability of some of the hardware I need to use as well as the core application i.e. VoIP switch is all developed and best supported on them. However, the driver argument will fail if I'm unable to install the RPMs built for RHEL on Fedora. Is that usually seamless or is there some package conversion, unpack, convert, repack kinda voodoo magic involved?