There are multiple strong opinions, as this lens is a POS physically. When it works it's great. I've had no problems with AF performance or inconsistencies and images are always great (f/1.4 has a more than the average softness, but this can be an advantage if you feel like exploiting), but it must be babied. I'm on my third round after repairs, I learned my lesson after the first but apparently not quite well enough - the last time it broke it was literally because I was pushing the lens into a foam cutout storage case. Yes, you heard that right, the pressure of pushing into foam broke the USM ring. My lens hood is now permanently in place and I won't use any filters on this lens, and always fully retract before putting lens cover on the front. Maybe this time it will last a few months.