Pink camo version M&P15-22 here has held up very well - although it seems to be more of a Duracoat/splatter paint finish than the hydro-camo Real Tree.
My first camo gun was a Winchester SX-AR, which is Mossy Oak Brush. It quickly became one of my favorite camo patterns as it seems to blend in well with a lot of the locations I frequent. My camo fetish continued with a Remington R-25 in Mossy Oak Treestand.
I passed on a Real Tree M&P15-22 and still wish I would have grabbed it - even with the accompanying 10 round mag - for more than $399! Excellent score. You'll find the camo finish very durable.
I've been considering doing this same hydro-camo coating process to several other samples. Won't rest until I setup a snow camo varmint eliminator...
Maybe I should hydro-camo the M&P15-22P as it sure has been seeing the most usage. Man that thing is fun to shoot!