I didn't like the loaded chamber indicator on the new MK IIIs so I decided to stick with my MK II with heavy 5.5" bull barrel. I love it, too bad Ruger didn't decide to make an updated MK II with American style mag release, rather than the heel release. That said, the heel release on the MK II is pretty simple to work. Most of its a case of personal preference. The .22/45 has the same grip angle as the 1911 pistol. If you like that grip, you might find it more comfortable than the standard grip geometry. If you can, I'd try to find some GunNutz close to you who would be willing to let you try their guns. Holding them in a gun store is one thing, but actually getting a chance to test fire them can really help. Might want to try a gun shop/club that has rental guns as another option.