Honestly couldn't tell you the differences between via and nf2.....but I've had an XP-M and with it I used the NF7-S v2 so it's the board to get, plus there are a ton of modded BIOS's out there for it
For the Athlon XP line of processors, nVidia rule. The Via KT line couldn't compete...at least I never witnessed it even getting close lol.
KT333, 400, 600, 800...all dwarfed by the sheer speed and flexibility of the nVidia NF2 boards Abit NF7-S v2.0 and the DFI Infinity were constantly competing for the top spot. The DFI could be proven better with lots of mods and work, the NF7-S v2.0 was bettter out of the box and was on par with the DFI. Take your pick.