If your priority is between F/1.4 and F/2.8, go for the sigma. Sigma is quite a bit heavier, more expensive, has better bokeh, and wide-open sharpness.
I think it's the better 50 especially on APSc.
My Canon EF50/1.4 had some mechanical problems and this is not that uncommon for the model.
I'm sticking to it partly because I'm using FF and seldom need to shoot at 1.4, and by 2.2 it's pretty good already. For similar angle of view of 50 on APSc, I'm using 85/1.8 and it's much better mechanically and optically.
Opinions are biased and based on personal experience that may be totally inapplicable to you. Therefore not that precious.
But the ability to read reviews is much more precious:
http://www.photozone.de/canon-eos/521-sigma50f1450d
http://www.photozone.de/canon-eos/159-canon-ef-50mm-f14-usm-test-report--review
Yeah I agree with you. Saw some sample pics between the 2 lenses the Sigma got better Bokeh compared to Canon. I think is because of Sigma is 9 rounded aperture blades. Sad to hear your Canon 50mm lens got problem. Is it still under 1yr warranty?
canon is easier to sell?
Is he a photographer or a shop owner? I'm guessing you're the latter if that's your main concern.
i beg to differ..
after i started in june'10,
i have change a total of 05 lens!
reason is, after shooting for awhile, i realise my forte and interest,
my needs changed.
therefore a change in lens.
and through selling, i also realised that my canon sell easier and faster.
no, i am not a shop owner,
neither am i a trader for lens.
To me that shows a lack of research before buying... you could have rented instead.
Is it all Sigma lens need to calibrate to your camera body in order to get the sharpness?