I've owned two copies of it. I just can't justify its performance over the alternatives any more, especially based on cost. My favorite autofocus 50mm would be the Canon EF 50mm f1.4, only at f/4 and above. What a performer. I wish the 50L had something more to offer than build quality.
LoL I must be a mirror image of you I had 2 x f/1.4s both of which had USM failures shortly after the warranty ended, it's the build quality that pushed me towards the f/1.2