One thing is for sure; Athlon is definitely gaining quite a bit of performance once running at a 133 MHz processor bus. Even if teamed up with normal PC133 SDRAM only, the AMD processors are able to gain a few percentage points.
Of course the story looks a lot better with DDR-SDRAM, because this memory type offers the same peak bandwidth as AMD's SocketA processors. The performance difference between AMD's 760 chipset and ALi's MaGiK1 however shows that DDR alone doesn't necessarily buy you a whole lot of performance. While AMD760 provides quite a significant performance boost in most applications, ALi MAGiK1 is not able to make proper use of the benefits of DDR-memory.
Right now platforms with VIA's Apollo KT133A chipset might not be able to provide the highest performance, but owners of PC133 memory could use those motherboards as excellent overclocking platforms at the price of a new motherboard.
People who want to get the most out of their Athlon or Duron processors will have to invest into DDR-SDRAM. If you then have the choice between AMD760 and ALi MaGiK1-platforms, you should obviously go for the AMD760 chipset. However, right now neither seem to be available and it looks as if ALi MaGiK1 motherboards will hit the shelves earlier than boards with AMD760. So if you can't wait, you might have to go for the slower chipset. I personally would wait for AMD760.
Iwill and ALi have already improved the performance of the KA266 since I received my first sample. Maybe there is still room for more tweaking and MaGiK1 will finally live up to the expectations. Right now I don't foresee a particularly bright future for this chipset.
What we are still waiting for is of course VIA's KT266 chipset, which will finally provide VIA's own DDR-solution for Athlon. Maybe it will even be able to compete with AMD's 760 chipset, but so far I don't even know when it will be released.