your doing this a little backward aren't you? Your suppose ask for opinions then buy.
I don't own a cmmg atleast not yet I've only heard good things about them not so much as one bad thing
Really there is no telling who makes what part there are so many parts that are manufactured and re branded
Whether it's true or not I've heard that cmmg, dpms, colt, RRA as well as others are made by LAR grizzley but I have not read anything confirming this I've also heard that DPMS manufactures 90% of the smaller parts such as springs, detents, pins mag releases, selectors ect and distributes to other manufactures for their builds
Due to confidentiality agreements I'm sure we as consumers will ever know who really makes what part
The only thing that is really important is that you like and enjoy your new EBR