I should have known better: if it ain't broken, don't fix it. My main system is a 64 bit machine which, until yesterday, ran Fedora Core 5. On top of that I ran several 32-bit distros in VMWare.
The system was just fine, yet I decided to get adventurous and upgrade to the new Fedora 8. Big friggin' mistake. First of all, the installation DVD got consistently stuck at about 30% of Checking dependencies in packages selected for installation...
So I grabbed a Fedora 7 DVD which I burnt a while back and never got around to play with, and tried it out. The upgrade worked (I could not afford a fresh install, since I needed to keep my data). And I should have stopped here. But no, I got greedy and retried the FC8 DVD. No more hanging at checking dependencies... hurray! But wait.
After rebooting the system, pirut (the front end to YUM) does not work anymore (crashes every time), the Gnome desktop forgets to repaint after a while and looks like a Windows 3.1 desktop back when an application leaking GDI resources messed up the entire machine.
Oh, and because of the new 2.6.23 kernel, I had to recompile VMWare's kernel module, which would have been ok, had it worked. But in the good old tradition of kernel developers who don't give fudge about backwards compatibility the kernel source is now incompatible with VMWare Server 1.0.4.
I always thought that it would be easier to test my software if I limited myself to fewer distributions. So thank you RedHat, you are out.