All over the web, there are a million different stories about this lens.
My personal experience has been nothing but great. The AF is pretty fast, the lens is pretty sturdy/well built. The lens is super light, sometimes I look at the camera to make sure it is still there. The lens has not 'missed' since I have been using it.
The results of this prime are dependent upon the photographer, plain and simple.
My results are not as consistant as I would like, but that is all a result of my inexperience. I can say I have improved with this lens, and I love shooting with it. It really makes me watch the lighting, length, angle, composition, etc... The color/contrast is very rewarding.
Get it, shoot it and enjoy it.