I dunno how someone finds the MR1 heavy. What are they, 8 lbs? Mine was light IMO. Everyone who complains about them only wants an AR and should stick with that. Its not an AR. Mag changes are fast if you know how to do it right.
Reliability is like the Mini 14. With good mags they don't quit. They pretty much clean themselves and can go forever without a cleaning or malfunction. They still have the ergos of a shotgun and very limited aftermarket support. Its one of the few .223 semis that you don't have to worry about breaking down or malfunctioning. If the ergos dont bother you then you will probably like it. If all you want is a non-restricted AR then you won't like it. You'll probably hate it. XCR is the best option for NR .223 most like an AR but it is still not an AR. Its a somewhat goofy bastard child of a drunk AR and slut AK... You'll probably love it

I did