Nothing beats a Colt
I was recently in the market for the same gun. I had just finished my RR AR build and came in under budget, so i figured i would add a dedicated .22lr AR platform to the collection. I shot the Mossberg Plinkster but it was extremely picky on ammo. It also was the cheapest feeling out of the three i tested, it truly felt like an airsoft or toy gun. I also tried the S&W your looking at but it too is somewhat picky on ammo (it even comes with a list it doesnt recommended). It was a better feeling gun than the Mossberg but it too is made entirely of polymer. It did feel more gun like with all the workings of a traditional AR and similar break down, and it was slightly more accurate than the Mossberg. Then I picked up the Colt M4 .22, this is one nice gun. It has a forged lower and upper giving it a "real gun" feel. It was the easiest to breakdown and clean as well as being the most accurate of all three. My only complaint was the trigger pull, its right on par with an AR and similar guns but its not the "Colt" trigger pull I am accustomed to. It is the one I own and now love, its a ton of fun for a fraction of the cost of shooting your. 223. But with the same feel. Hope my review helps you make a decision, I know my mind was almost made up from just holding them (Colt) but after shooting all three it was a hands down decision for me. Good luck and let us know what you decide on.
Ride safe! Shoot safe!