Actually, I think the 50 F/1.4 is a great lens ... although commonly, casually and easily maligned anywhere you care to look. Aside from being a little fragile, it is hard to fault it. It makes great images.
I've had it twice, firstly on crop (10D) I liked the focal length but it constantly missed focus at f1.4 when shooting anything that moved. Ring-type USM is rubbish, frankly. Tried it again on FF (6D) and found I just didn't like the focal length and it still felt badly put together. Pretty bad CA wide open as well. Upgraded to the 85 1.8 and I'm much happier.
There's just much better alternatives now if you like that focal length.