For me, I would opt for the 1911. I know people have their misgivings about reliability in a 1911 with less than a commander length (4.25") barrel, but I have never had any issues with my OACP. The only FTF that I have ever had was with a new recipe for handloads, and there were about 8 out of 500. Since it was all range fodder, I don't worry about that much. With factory loads, it is 100%. Plus, I just love the feel of a SA trigger!
Furthermore, I like the capacity of autos, with the ability of quick reloads. Yes, I understand there are those out there that can reload a revolver faster than I can a semi-auto, but most can't. I would give up the slight edge of capacity of the 9mm for the awesome man-stopping power of the mighty .45 acp (ok, I got a little carried away there).
Also, I find it interesting to see the responses that are garnered on a site like this. Post this same question on the 1911 forum, and you will get an entirely different set of responses. To each his own.......