Well, for me, the Ubuntu 6.xx installer hangs on my system with no error messages, both Fedora 7 and Ubuntu 7.04 have a horribly broken X on Intel G965 chips (Broken native mode setting and broken GL). Fedora Core 6 works just fine though, so I'm staying here for now. Yum works well, building stuff (including custom kernels) from source is a breeze unlike Mandrivel was, and no ports were open by default. Hopefully the Intel graphics driver devs will fix the 965 support for the next round of releases.
I don't consider myself a fanboy of any particular distro. I just use whichever works best for me at the time. I used to use Mandriva, but that really started to suck after the LE2005 release...