My Tyan S2460 has been the best and most stable mobo I've ever had -- and that's saying something. It has served me well for about 2 years now, I've upgraded my two CPU's in it several times, I now have 2x 2000XP's in there.
Yes, it's true that the dual boards don't have some of the nifty new features such as SATA and such, but my experience with the dual AMD boards has been that they are extremely stable and reliable, and for certain applications having a dual processor setup is a must. For example, if you run a server, you're better off having 2 x 2100xp processors than with 1 very fast one. Also, if a process goes awry and pegs cpu usage at 100%, you still have the other CPU running normally, so you can diagnose (and if needed shut down) other processes.
I'm a big fan of the dual AMD setup. I wish there was an equally affordable new dual board with all the new features...