I'm going to make one of those stupid remarks "I don't have it, but..."
The fact is, I don't own it, though I have seriously looked at it, including a couple years at PhotoExpo. From everything I have gleaned, it is an excellent lens, especially for the money, well corrected. Being a prime lens, it will almost always be better than a zoom, especially a wide angle zoom. Don't get me wrong. I own many zooms (Canon 16-35, 24-70, 70-200, 100-400). I love them for the convenience. However, every one one one my prime lenses is sharper and better corrected (35, 50, 85, 100 macro, 135).
If you have a need and don't mind not having autofocus and have another lens within that range (say a 24 or 28 or 24-70) and have a real need for it, go for it. The only thing that has kept me from buying it is that I rarely use super wide lenses, so my 16-35 will make due.