The 'Colt' is a glorified airsoft gun, as stated above. Already having warranty issues with them, as Umarex is a bit overwhelmed and Colt is not standing by the product that bears their name.
The M&P is light years better, but, as mentioned above, its getting a reputation for puking extractors. If you pick one up, might as well have a spring, plunger, and extractor in your 'Oh, Shyt' kit. Keep the extractor clean and well lubed, as most of the ones I've seen come back are dry and dirty; extractors tend to walk on most autoloading .22LRs if they're dry. M&P advantages? Any AR trigger will drop in, and sights, lights, and any other tacticool stuff you can hang on your AR will hang on it.
Personally, I think a gussied-up 10/22 is the way to go, as they're proven, reliable, and have TONS of parts you can use on the one you build. I'm just partial, though.
Its better to sweat in peace than bleed in war...
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