Just bought a copy of this lens here. The lens is build very well, and has some weight to it (to be expected with a f 1.8). Love the DOF on this guy, but when you get up close for macro, the AF steps the focus 3 times before it locks in. Not a huge problem, because I usually manual focus when that close.
Center sharpness is good, not excellent, and the edges get soft (but not surprising). But over all, for the price this lens hits the mark in build and IQ, its a keeper.