I have the cheaper CMMG parkerized kit and have never had an issue. Have run it with 1000s of cheap bulk 22lr without problems for about 5-6years. After every range trip with it, I shoot a mag of .223/5.56 to ensure the gas tube is clear of any 22lr crud. Read a bunch about break-in but mine didn't require anything special other than a good cleaning oit of the box with Hoppes and a good lube with Mobil1. Accuracy isn't great, but fun at 50. I recommend it.
If you go this route consider using the “better mag adapter” which is available for short money and allows you to use the S&W 15-22 magazines. Those mags are very reliable and available in 10 round if you are in a non free state. Mag well adapter slips in and out without modifying lower.
Just finished my second dedicated .22lr upper. Lots of fun. Same operation as Ar 15 so good trainer.