Well, I don't notice any difference between my 9mm Springfield Loaded and my 45 Kimber Custom TLE. Safety is the same, trigger is the same, weights are very close, sights are basically the same..... For self defense purposes, I don't even think my Kimber Compact would make any difference.
Oh, if I were a precise target shooter, I might be able to tell the difference, but neither of these are "target guns" like my Gold Cup, which I would not use as a carry gun.
While Ayoob, et al, have a point about practicing with what you carry, remember, police have different situations than the person carrying a firearm for self defense. We do not have to pursue a criminal, nor take shots at longer distances. Most self defense shooting are at close range and I really doubt that the difference between a 9 and a 45 would be noticeable to us in an emergency situation.
Now I would definitely see a difference between say a Sig P220 and a 1911. In fact, that's why I bought the full sized 1911, I didn't want to be switching back and forth between a DA/SA pistol and a SA pistol. But I think that there is no significant difference between various 1911's for normal self defense use.
BTW, I don't have a problem with my wife, she shoots too. I gave her 800 rounds of ammo for Christmas
When I came home with the new 1911, her comments were "oh, that's beautiful!" and she liked the trigger too
We both have our CCW licenses.
BTW, I reload, so practice ammo is a little more reasonably priced.
Ken