Wide open the much less expensive old Minolta 50mm Macro outperforms Canon's 50mm f2.5 stopped down to f2.8
But wait, there's another twist....look at the out of focus areas in front of the focused areas. Though the Minolta was visibly much better wide open, it has some ugly rendering in this area.
Stopped down there's little difference in the sharpness of both lenses. But the weird rendering of the Minolta was something of a disappointment. Though honestly if I wasn't looking at results side-by-side I don't know if I'd care.