bit-tech published a comprehensive review of the Asus Maximus Formula & Maximus Extreme motherboards
If you are a performance nut, it helps, because there's tonnes of options to play with, but even if you aren't then a single click to "Crazy" in the BIOS will shoot that CPU so high it'll end up in orbit. The EPU, again, works fantastically on the Extreme at least, and you don't even need to worry about the future X48 chipset, because this board will work stably with 1,600MHz FSB CPUs, even if the support is "unofficial".Asus Maximus Formula & Maximus Extreme Review
I'm not going to deny the boards have left me a bit deflated, despite the whole host of features - they just hasn't really done it for me. The Extreme is mightily expensive and requires expensive DDR3 memory, which unfortunately puts it out of most people's league. Having said that though, its featureset means it's not designed for those that want of cheap - it's designed to be awesome. And it does that bit pretty well.
The Formula might be DDR2-based, but it hasn't shown itself to really be a worthy purchase. Personally if I wanted a DDR2-based X38 board, the cheaper Asus P5E or Gigabyte X38-DS5 are now / /far more appealing (oh how the benefit of hindsight grates me for only giving it a seven overall) and I'll use that extra ?30/40 to get a faster graphics card - they both have a far more appropriate price:performance ratio.
The Striker Extreme II board is due out soon for you SLI nuts, and there should also be a board based on Intel's X48 chipset too, should Asus have plans to update the Maximus with that. If I had the money and I wanted a DDR3 board then the Maximus Extreme is the only motherboard I've seen thus far that's worth seriously considering, but if I wanted the a more cost-effective DDR2-based board, just get what I suggested above or try to grab a second hand Blitz Formula.