I'd get the Canon being there is not much difference in price.

The Bigma is kind of iffy. The peope giving it good reviews alway seem kinda soft on Sigma and Tamron (advertisers maybe?). I only consider 3rd party when it get all around reallygood reviews and is much cheaper. 6.3 is awful slow.

You could at least rent the Bigma to see what you think but I wouldn't buy it sight unseen.