I would say that the new core revision AMD's are just as goo as the P4's (XP2400 and 2600). However, I haven't OC'd one myself, I'm going off of one of Tom's articles. The P4's have been getting good oC's for awhile now from lots of people. Most of the time, I would say go with what is working (p4's).
[rant]AMD, YOU ARE EVIL!!! GIVE US WHAT WE WANT!!! A STOCK, UNLOCKED CPU!!![/rant]