Did you actually ask that Q?
The canon lens would be WAYYYYY better...the sigma will save u $$$ but the canon lens is on par with NIKON which are supposed to have the best lenses in the industry!
Thomas Edison said,
"I have not failed. I've just found 10,000 ways that won't work."
Think about that the next time you want to give up after 2 or 3 attempts...