I'm torn.
My favorite 45 is my Colt 1991 Officer Model. It's a great shooter and functions flawlessly so far (I have about 2000 rounds through it) When I got it I shot 500 rounds before cleaning to see it when it would not function. It hasn't malfunctioned yet, but I do clean it every 300 rounds or so.
The only disadvantages to the Colt is that it's heavy to carry, pulling my pants down if I don't wear it on a belt outside the belt loops; and it will only shoot 230 grain ammo without changing the recoil spring.
My other 45 is a Sig-Mauser (Mauser imported by Sig). It is lighter, a little bulkier, but it will shoot anything I feed it without modification. I sometimes prefer 185 grain bullets in it. I have to admit I don't have a consistent opinion of the best round for defense -- I have a shifting opinion from time to time.
Overall, if I knew I was going to be in a fire fight, other than sending someone else, I would prefer the Colt.