I just went through the S&W armorer's school for M&P pistols, and think they're pretty nifty guns. They're smartly designed and pretty easy to fix and work on, but so are 1911's.
If I was making a choice, it would depend on use. Either one would make a good duty weapon, but if you're "collecting" my choice would be the 1911, simply because it's a steel gun. S&W has a new line of 1911's out also, and I haven't seen a Ruger SR-1911 yet, but since everything is CNC machined these days, I suspect that any of the manufacturers offerings will be pretty consistent with their competitors. I handled a Remington R-1 recently that was smoothe as butter, and most of the new guns I've seen with CNC parts are all pretty consistent in quality. Like the old days, the differences lie in spring choices, trigger work, and attention to details.
I can't really say how Ruger's 1911 is, but I've seen the new S&W's and they're excellent. Great machine work, and great finishes... and they all seemed to run like a Swiss watch. Shooting the M&P, one of our salesmen who is also an animal control officer, outshot the entire sheriff's department qualification class he attended, so apparently they work well too...
When I'm selling guns, I tell people "you can spend as much money making the same bullet go 'bang' as you want to spend"... and most of the time, the choices are made because somebody likes one gun over the other for whatever hidden reasons they might have. They're both great guns, and depending on whether you have an M&P fetish or a 1911 fetish, you'll probably decide based on your own prejudice rather than anybody else's.
If you settle on the M&P, I would suggest signing up for the armorer's course just so you realize its potential. They are extremely versatile.
WT