comparing Pan 7-14/4, Pan 12-35/2.8 and Oly 12/2 at 12mm

I have the Olympus 12mm f2.0 and have enjoyed the little lens. I'll be honest in saying that I don't think my copy is as sharp as everyone else says their copy is. That's why I keep thinking about selling the lens, but the truth of the matter is I keep finding myself in poor light conditions and I realize I wouldn't have been able to manage without the damned thing. Maybe it's just my style of shooting that makes having a fast lens important to me and thankful the 12mm delivers. In some conditions even that 1 stop makes a difference.

Note: I do also have the 20mm f1.7 but often it's too narrow for what I want, and the slower focus really burns me in some cases.