First of all, maturity is a long evolving process that does not necessarily assure high reliablity or high performance.
I don't see the AMD760MP as being 2nd generation. From what I've read, it is the very same design as the present AMD760 extended to accommodate multiple processors (which provides only limited benefit on the desktop).
So far, the IWill KA266 board (based on the ALiMagik1 chipset) has been extremely reliable, if not a KT133A killer.
While some say that MSI's K7Master is the best DDR board so far, it is very expensive and very hard to find.
Based on their design, the VIA KT266 chipset boards (due out in a few weeks) promise to be the best performing of all DDR boards, if not the most reliable (VIA's track record for reliability is not the greatest)!
PC2100 DIMMs (which are reliable) are becoming more available and less expensive.
IMHO, that's where DDR is at right now...