I've been fortunate enough to test almost all of the dedicated 9mm carbines (not AR variants) on the market having really liked the Marlin Camp 9 that I sold many years ago to pay college tuition.
Anyway, the JRCs have not been reliable and there have been some that had problems that put them into the dangerous category. If you are looking for something not an AR and not cheap, the best bet is Thureon Defense. I have run them in 9mm and 45 with both modified steel and Glock magazines. I'll be testing a 10mm version this December.