I've been involved in plenty of these forum discussions about the 1911 for duty use. I have never understood why someone would choose a low-capacity, relatively complicated pistol when you have bulletproof high-capacity modern designs like the M&P available.
Having had more of an opportunity to play with 1911s lately, I absolutely get it, I really do. I still don't know if I'd choose one, but I think I'd feel okay with a relatively high-dollar, quality-built one like a Colt XSE, Dan Wesson Valor, or Springfield TRP.
It astonishes me how comfortable the platform is, how amazing the trigger is, and how naturally it points. You might only get 7+1 or 8+1, but I feel like I could do a lot of damage with 8 or 9 rounds in a platform that inherently easy to shoot. Get a quality one and run it enough to make you feel okay about reliability with ball-profile JHPs like the Remington Golden Saber, and I can see a convincing argument for the platform.
Beretta PX4 .40 S&W - Colt 1968 Detective Special .38 Spc. - Ruger LCP .380 ACP - Daniel Defense M4V1 Carbine 5.56x45 - Ruger 10/22 .22LR - Remington 870 Express Tactical 12GA - Mosin-Nagant M91/30 (Excellent) 7.62x54R