What was wrong with AMD 760? I've never used one myself. I know they were usually paired with a VIA or ULI southbridge. A friend of mine had one of those boards, with a VIA 686 southbridge. I think it worked fine for him. Ran a Tbird 1400 and Radeon DDR.
Oh wait, those had AGP problems with some cards didn't they? That would be annoying....
The only well-known problems with KX133, KT133, and KT133A are the southbridge and bad BIOS programmers setting registers incorrectly. You could get nasty data corruption on the PCI bus when some cards are used. But I did have a rather trouble-free experience with a Abit KT7A KT133A mobo.
KT266A and onward were the best of VIA, IMO. New southbridges with much faster interconnect. Really great DDR memory controllers that matched nForce's fancy dual channel + DASP L3 cache in app performance.