I love my CSA in 5.56 (non-restricted). I got one of the very early model, which had a turned down 7.62 firing pin that snapped off after ~400 rounds. It's now replaced with the new 5.56 firing pin and it works well so far.
The best addition I did was putting a railed dust cover (from Zahal) for optic, but with the original stock it was hard to have a good cheek weld, so I opted for an AR straight stock adapter.
The original magazines are really good, very reliable but are limited to 5 rounds. Being plastic can also be a turn off for certain people, but they are great mags nonetheless. Since I have one of the very early model, I won the lottery of free machining (they don't require it anymore) and free adapter from North Sylva. The mag adapter is plastic and I read horror stories but I have no issues with mine so far. Mine doesn't like Gen2 PMAGs but Gen3 are fine. LAR-15s are fine, XCR pistols are fine. I also had feeding issues with some ASC mags that I later realized are 7.62 5 rounders and not 5.56. I tried a shell deflector (before having the railed dust cover, with a scope mounted with an AK side rail mount) and it caused a lot of FTE, so I don't recommend it.