I've never understood why people think it fixes everything at low frame rates. If you stand still in a point in game and spin around 360 degrees, what *-sync does is try to split the 360 degree into equal sized slices rather than very different size slices.
You can get a stuttering feel two ways in this scenario, where the slices are very different sizes, and where there are simply not enough slices. *-sync helps fix out the first type of stutter, it does absolutely nothing for the second type. The higher the framerate the more slices, the smoother the turn feels. Low framerate is itself a source of stutter. *-sync works best, IMHO, in the 70-144fps range.
There's also the fact that the refresh rate has been drastically lowered and looks flickery and non smooth as a result (and gives eye strain).
I might be interested in a 120-240hz asynch range in future, but as of now the technology is useless and completely counterproductive to me.