I really gota say here,im thinking exactly the same,NEVER ever have i seen any microstutter in any game.
I have had 5870 crossfire 2 times now,using 4 completely different cards over 5 different motherboards with 3 different cpu's and 2 different socket types,over x16 lanes-over x8 lanes.
Never once have i experienced microstutter using any drivers.
I have seen that yes,there are benchmarks etc that show this to have happen but its something that i myself have never ever under any circumstances experienced.
5870 crossfire is not to be sniffed at especially when you also do the enableulps mod to registry which forces cards to both take full loads.
If it was me id likely get on ebay and buy a used 5870.
I ran my crossfire rig over 1980x1200 and i was extremely impressed with FPS in any game.
Made me have big cheesy grin thinking that i could now play any game maxed with >60FPS
I also had mine watercooled and clocked to 1ghz cores,performance was amazing