Hi,
since it comes up every now and then, I'd like to get the differences clarified, especially since there are ideas to get them united, which if the contents and target groups are too different would be wrong.
The way I see it it is like the following:
o fedora-devel - concentrates on rawhide and its way to a release - has in-house upstream development discussion - more in-depth Linux mechanics - manages release cycle
o fedora-maintainers - concentrates on the packaging community as a whole - More issues about packaging than on upstream development, if any - cares more about current and past releases
There is some (IMHO) healthy overlap, but I do think that they differ enough to keep them separated to have each group enjoy a better SNR level.