Some bad advice...
Now I have plenty of problems relating to having installed packages from rawhide* and such, so perhaps I'm not a good person to ask. But I have used synaptic since Rh9, and I believe it is installed by default in Fedora Core. (If not, it's a little tricky to do it manually, but it solves a lot of problems if you succeed).
I have apt and synaptic installed and pointing to the repositories at freshrpms. The freshrpms site includes instructions about how to set it up like that. If you only install their official packages, you are pretty safe from conflicts and broken/undocumented dependencies.