Microstering is not a problem with right system setup and game settings. It is old story, and it was mainly problem with older CrossFire and SLI cards.
I had the HD 4870 x2 no problem, the reason I bought the HD 5970 and now waiting for HD 6990.
I'm sure not an idiot to punish my self with microstutering if it was the case.
The microstuttering problem is old tale mostly repeated by people that never used the CrossFire or SLI with the newer cards edition or never had any CrossFire or SLI period.
I can safely bet that most people using SLI or CrossFire with the right setup have no such problem. Also I can safely bet the minute Nvidia comes out with dual GPU card, the problem will go away with some people.
Some people just have a HUGE problem to read something positive in this AMD Cayman doom and gloom review thread. Beside I was not even posting my own experience.
Go read again
here or the other CrossFire review in the OP.