I shot one before I bought my M&P 15-22. It shoots really well. I got a better deal on the M&P. I didn't do my research on magazines. I was told you could only use Sig mags and having owned Sigs before I knew they were proud of magazines. In reality, it shares the same mags as my CMMG. Had I known that I might have bought the Sig even though there was a price difference. The M&P feel like my CMMG...only lighter.
I first bought the CMMG Quebec A first. Last week I bought the M&P 15-22 so I could have 2, tactical .22's. I shot the 552 before purchasing the M&P. Both are good guns, but not in the same league as the CMMG IMO since it can be upgraded to a .223, etc. The only thing that scared me off the Sig was magazine prices. I have 7 magazines for each of my guns (pistols and rifles) that's serious money in the Sig world. Edit: When I bought my M&P I didn't do the research to see if the magazines my CMMG uses could be used in the Sig. Short answer.. they can.
I have a CMMG Quebec A .22 and a M&P 15-22. I had issues with both at 2 different indoor ranges until I let one of the guys shoot them both. Now I have no issues and I think I've helped them sell quite a few .22 AR's. ;D
I own a Quebec A. It's a quality piece. I bought it because it's a real AR and the upper can be swapped. I also got a .223 upper and a 9 mm upper when I bought it.