I love my Sigma glass and the support I've gotten from them in the past. That doesn't compare to what my brother went thru with them sorting out why their 120-300mm f2.8 Sport wouldn't focus with his Canon 1D. They sent him replacement lenses while his was sent to Japan for the engineers to look at. Turned out it was a weirdness with the 1D firmware, something they managed to sort out and eventually fix in the lens' firmware. He was the only human being who ever raised the issue with them. I can't imagine getting that kind of response from other companies.