Yet another which lens, 20mm f1.8 or 2.8

[Scoobydougie]

Has anyone here any experience of the Sigma 20mm f/1.8 EX DG ASPHERICAL RF http://www.sigma-imaging-uk.com/lenses/wide/20mm.h...

I was initially looking at the 20mm 2.8 canon lens, but the Sigma is slightly cheaper and is f1.8 which seems tempting, just wondering if anyone has either and any comments.

Thanks in advance!

[looop]

I had one, At F1.8 its quite soft, but from F2.2 and up its very sharp.

Loud to focus though.