I am going to be an even bigger heretic, I shoot both Nikon and Canon, both film and dig, and I was bored and curious so I ordered a Yongnuo 50mm 1.8 to replace a broken Canon Nifty 50 (the breakage was not the lens's fault, the lens was dropped on a concrete floor when the strap broke (grumble grumble)).
ANYWAY, bottom line is I like the $40 Yongnuo better than the Canon I replaced it with. Very sharp, but what really shows is the Bokeh is MUCH better and that's one of the most important things there is to consider when buying a fast prime.
Normally, I don't shoot off-brand lenses but I thought I would throw this out there because that thing is so darned cheap you can buy it AND another prime and have the best of both worlds.