...as are the comments about poor AF performance from those who don't use one.
"Poor AF performance" is definitely not true...but I can say from experience that the 5DII's AF performance is not as good as the 7D, and the 5DII has trouble tracking moving subjects where the direction of movement is toward or away from the camera (although that's probably a combination of less effective AF and longer shutter lag).
For stationary subjects, the 5DII's center AF point is excellent. The off-center points, besides being insufficiently spread out, are single-orientation points that sometimes hunt for focus, in my experience.
Out of interest, do you find this holds true with slower lenses that don't activate the cross type sensors?