Some users, myself included, are experiencing random total lockups. The systems are freezing up so tight there's no way to get diagnostics info. It's affecting different video chipsets, different WiFi chipsets, some Ethernet users, there is NO pattern to the hardware involved.
A bug has been issued to the kernel team, priority high, marked "triaged":
Today I did a fresh install from the release CD, standard 32bit, Intel945 video, Atheros WiFi, all standard parts on an Acer laptop that handled Feisty and Gutsy like a champ. No overheating. 1.5gigs RAM, swap stats show zero use so it's not corrupted swap.
I don't think the devs are going to be able to fix this one easily. There's just NO feedback or debugging info possible. When Fedora 9 releases I may be forced to abandon ship.
This really sucks.