I had the 35L. simply amazing lens!! If price was near equal, why buy Sigma? I'm not put off by 3rd party glass, a I love Tokina and some Tammys I've owned. I would try to get a used copy for about 700 or so once plenty are in the market....assuming the lens is as good as advertised.
because the sigma is a better lens than canon optically and mechanically? also someone would prefere the gold ring than red one