Main reason I never bought a P4. Too many socket revisions.
I stuck with Socket A.
Second main reason was that they are pretty rubbish 
I think you'll find AMD are far worse for socket revisions, although they did stick with Skt A for ages (arguably too long, which hurt their performance).
As to performance, no AMD Socket A chip has ever outperformed the equilivent Intel part in real world tests - though the Athlon does have stunning integer performance.
In 32bit arena, Intel has always been top dog (look at major manufacturers 32 bit workstaion and server offerings, always Intel). 64bit is harder to call, as most 64 bit server/workstations (the only sectors currently needing 64bit) tend to stick to non x86 chips such as SPARC and Itanium. There aren't many 64bit apps (true 64bit) for x86 chips, and OS wise you're looking at W2k3 or a handful of Linux versions, and Sun appear to have the 64bit Unix sewn up with SPARC/Solaris combination, HP being a close 2nd with Itanium/HP-UX. That makes Windows Server 2003 and Windows Longhorn Server the deciding factor on whether x86 64bit will be a success, rather than marketing bull.