Re: m&p 15-22
My Dad and I just picked one up. The first, and most important thing about this gun... is that it is one of the most fun guns you'll ever shoot! We've been feeding it cheap bulk ammo so I can't speak to it's accuracy. (I took the scope off my Rock River AR and mounted it up just to see what it would do, even with junk ammo, a pop can at 50yds doesn't stand a chance) I would guess we've put 1000-1500 rounds down it so far. It has jammed a couple times, but less often than your average ruger 10-22. I really don't have anything bad to say about it at all. It's great as an AR trainer(that's why we have it) The fit and finish is good. It functions very well. Get one and you'll love it. Just make sure you've got a ton of ammo, the little 100 round boxes don't last more than a few minutes! I'd also pick up an extra mag or two for it (and some one who will load em while you shoot!)
One thing that I wouldn't use it for is personal defence. Sorry, but the 22 is best left to plinking and gophers. It just doens't have any knock down power. An attacker might think twice if your packing what looks like an AR... but your not. For a personal defence weapon, buy a Taurus Judge revolver and get some shot shells for it. It'll change some ones mind about messing with you real quick, and the shot pellets will be less likely to make it into the neighbors living room.
Just my 2 cents.
I like things that go "bang"... I love things that go "BOOM!"