I have neither; however, I have spent limited time at the range with a Colt model 1911 among other handguns. I'm sentimental; however, I would choose the .45. It stops people. Browning designed the 1911 in part because of the US Army experience with the Philipine tribe of the Moros who would attack suicidally after getting hopped up on drugs. Many found the US Army .38 inadequate to stop these attackers. (See
The Sight: M1911A1.) This situation replayed in the Mid East where some service people have traded in their Barettas for M1911's. There is even a charity that collects funds to provide ground pounders with .45's.
From what I read, it's stopping power that matters, which is why I guess that double-tapping is important when using a 9MM. I also think that the 9MM is the one of the reasons why so many gangbangers survive multiple shootings. From the perspective of a defender, I don't think that surviving a shooting is a bad thing for the attacker unless the attacker is still able to return fire (is not stopped); When many attackers do survive multiple shootings, I wonder how many of these shot attackers were able to fire back. On another note, I wonder again if the small round is the reason why so many children get killed. Adults are much better able to withstand the round.
Browning was beyond genius. We're debating using his weapon almost 100 years after it was introduced. On the other hand, I've believed that the 9MM was a marketing deal. I don't think folks would have gotten excited about an automatic that fires a .35 caliber round. A 10MM, at .39 caliber, seems a bit more reasonable; however, this is very close to the .38 round that many police forces and military organizations had previously found inadequate.
By the way, for you M1911 adherents, the above site has an interesting page of
Myths and Legends of the M1911A1. My favorite is the pilot who used his M1911A to shoot down a strafing Japanese zeke while he was floating down in a parachute. So if your home defense may require shooting down airplanes, choose the M1911.