Well, after about 7-8K rounds, I feel that I have tested out the new S&W M&P 15-22. Size and controls are identical to any standard M-4 with the bolt locking open with an empty magazine (this doesn't happen on the Colt .22). I know the plastic doesn't seem logical but I have yet to even crack it. The removeable sights are wonderful, something you would normally pay $70-80 for. I was glad to see that S&W didn't skimp on those. I outfitted mine with an Aimpoint M68, Ergo VFG, and Surefire light. The gun easily shoots 2-3 in groups as fast as you can pull the trigger inside 50 yds. With the Aimpoint, it held 1.5" groups at 100yds off the bench, could probally do better with good glass on it. Just to have fun, I took it to a steel match recently and had a blast! Not a single malfunction throughout the day and really lit up the targets. I can finally run the pistol stages with an AR and not waste expensive frangible ammo!
Improvements: No place to mount a single point sling, as the buffer tube is fixed. I used some 550 cord and a key ring until my mount from Brownells comes in. The rifle does not like to be "topped off" as in inserting a full 25 rd magazine into it with a round in the chamber. It double feeds every time. Easy fix, just make them 24 rd mags! I discussed these issues with the Smith LE reps this week and the input will get passed up the chain. He did reveal that a M&P 15-22 MOE version is under way.
I have also discussed the possibility of a 10" integrally suppressed barrel for it with the guys at Gemtech. They, of course, were already working on something fun for the .22; you'll have to wait until after SHOT show in 2 weeks before I can reveal what it is.
For campground plinking, economical AR practice, or for safer LE shoothouse training, this is the way to go. The complete M&P 15-22 sells for just over what 1000 rds of .223 costs and is a great training tool. I expect many more LE departments to pick these up and start training with them. I know I will be....
-coloccw