This seems to be a staple lens that you should have in your collection. Unfortunately, for my style of shooting, I rarely use it. Maybe if I had full frame I would use it more but on a crop sensor, I don't find it wide enough for when I would want to use a prime lens (again, just my style of shooting).
I don't know if it is my copy of the lens or my camera (7D), but I have trouble shooting in low light with this lens. Maybe it needs to be calibrated but it seems I'm not the only one who has had issues.
Regardless of the issues, I guess it is still a lens everyone should own as it will come in handy from time to time.