well, for 90 bucks it punches way above it's weight at moderate aperture, and even at f2, is good on center, not great. Edges are another story, but you need to be a f4 or less to get good performance in the field.
compare it to the canon 50 1.4 and it comes away favorably, in other words, optically not much reason to spend 375$ on the canon. You do get a better build and full time manual focusing, but the wide open performance is not great, not any better than the 1.8.
canonrumors has it that maybe there is a replacement in the pipeline for the 50 1.4 coming since it is on backorder. maybe they are feeling the heat from the sigma which is better optically and also from the zeiss which is great optically but manual focus.
I think they could do better. the lens is from eos film days, could stand an update. Keep the price point around 3-450 or so, but then again, it would take away from the L sales.
why canon doesn't go the leica route and have a summicron-level performance line is beyond me. compact, high performance primes sharp wide open- moderate price. it would not compete with the L series, which are all super fast lenses. and f2 is plenty fast if it is good wide open. f2 on the current 1.4 and 1.8 offerings is only good on center, the edges suffer heavily.