I just installed RedHat 7.2 on a server I just pulled from the field so I could play around with KDE 2. Pretty sharp. Still not the yummy goodness of Darwin/Quartz/Aqua that is Mac OS X but its getting close. Supposively, Mac OS X is going to get a Linux compatibility layer for binaries soon from the LinuxPPC project.
On a side note, Apple actually made its own distro of Linux in the mid-90s called MkLinux. It was a test bed for the mach kernel that is used in Mac OS X.
I just brought up my redhat 7.2 box the other night. just getting into the nuts and bolts of it - I do like KDE.