Canon 10-22mm or Sigma 12-24mm?

If you have a choice between the two super wide angle zoom lens, which one would you choose, given that the Canon is slightly more expensive. $799 vs $669.

I just got the Canon 10 to 22 today and did a preliminery test. See my post 10 to 22 mm Lens Test.

I'd get 12-24 cause I'd wanna distort some lines on a BW film camera.

Along the same lines a what the Good Doctor has to say...

Of the two,. personally I would need to get the Sigma becuase it will work on all the cameras I own.. The Canon will NOT work on a 1DMkII,... or a 1D of any type for that matter.. film or digital.

Thanks CDS, that is a very important point. Use on a dRebel, the Canon becomes a 16-35mm while the Sigma is 19-38.5mm. The extra 3mm on the wide side is very tempting for me....choice, choice, choice.

Ok I did a new test on a tripod and I did it at F22 and the photos were totally unsharp. I will bring it back today and get the Sigma.