Yep, I installed the newer yum to get the more efficient metadata representation. (The tricky part was that one has to hand-update any customized yum.conf to include the new /etc/yum.d files, as yum.conf is marked noreplace. But this might have been addressed in more recent packages by a post scriptlet.)
Eventually FC3 will move to Legacy and will need this, so effort to set up the mechanism wouldn't be wasted.
Yeah it's just an extra line in our 'upload' script. It will add a few minutes on our end is all. I'd rather not gen the metadata twice ):