Herman...
The Ultra Compact is not one I have personal experience with, but, in general, I'd be concerned about feeding reliability in the small format .45's. There is some real balancing going on to accomodate the recoil forces in the small format 1911 style pistols, and some are very sensitive to ammo, for one, and the operator relaxing his wrist, for another. I have a ultra small Caspian (steel receiver) I built that also strikes me as a bit heavy. In a carry piece my priorites are feeding reliability, weight, and finally caliber. A pistol that weights too much won't be routinely carried, hence you probably won't have it when you need it. If it jams when you need it, well, that should be self evident. Last is the issue of balistic effectiveness. (A hit with a .22 is better than a miss with a .44.) For all my years of experience with the 1911 .45, my carry piece tends to be a 5 shot revolver.