If you have the 2.0 Compact vs the 9c, you can get sleeves for the 17 rounders. I picked enough up to outfit all of my 17 rounders and they are really nice.You made me dig them out to check. I got ten of the 17rd ACT mags back in June for $20 apiece. Last week six used S&W 17rd mags came in from EveryGunPart.com. I got lucky on those,.....I had them in my cart from a month ago and they were all still there when EGP threw out a sale a couple of weeks ago. I checked the pics closely and weeded out any mags that looked suspect and watched for the 10rd mags to be sure I didn't get any of those. The work paid off,......all six are what I'd call 98% or better and on average cost me $18.63 each.
I haven't shot any of these mags so all I can give is a visual description and I don't have a full size M&P 9mm, just a couple of M&P Compact 9s with the 15rd grip frame so these 17rd mags extend a finger's worth when seated. Visually, the ACT mags are first rate and almost indistinguishable from the S&W mags. Finish is the same slick, hard blue. I don't know about any 'painted' finish. It's not cerakote or anything like that. Doesn't have any notable thickness to it. It's slick and all mags eject with equal vigor. The mags 'feel' quality, sharp corners, metal thickness and rigidity equal to the Smith mags. Insertion and lockup feels identical although I'm inserting 17rd mags in a 15rd magwell so if there's a problem with latch position I wouldn't be able to tell.
Just judging from 40yrs of handling and owning hundreds of pistols with both OEM and aftermarket mags,.......these things seem to be fine. I *think* they're MecGars and I *think* the OEM mags may be as well. I'd heard that rumor before. Generally I shy away from aftermarket as we all probably should. The cost of ammo necessary to prove reliability of even a 'good' aftermarket mag far overshadows the extra cost of OEM mags, but these will prove themselves on the range eventually. I've got enough OEM 15rd and 17rd mags for carry and they'll see little range use. I'll beat the ACTs and see how they hold up.