@md7 and any others who want more info on 9mm blowback ARs I suggest this site:
No-BS information for the 9mm AR.
blowback9.wordpress.com
I have 2 Ruger PC Carbines and an M&P FPC. I've owned a PSA AR9 and a Marlin Camp 9. The FPC, despite being the lightest, has the least felt recoil.
I like that the Response is made in the U.S. by a solid company like S&W. It's a refinement of guns that have come before, nothing radical in design.
This rifle might be an introduction to some who haven't embraced AR style rifles being in a less expensive caliber and using the same mags as a pistol you already own.