I have one and had been using it for several years without problems, but I removed and replaced the factory gas key and screws when it was still new before I used it.
What the other members said was correct the CMT comes in two grades, the lower price ones are not MPI tested and the higher priced are tested, with the info I got before I bought mine they're all batch high pressure tested, they're also comes in two versions semi auto and full auto carriers.
Mine have the not the usual stakes on the carrier key screws, seems like someone just put a chisel on top of the carrier key screws and hit it with a hammer.
I don't prefer that type of staking so I replaced it with a new BCM gas key and screws, when I removed the original key screws they didn't even have any resistance, like they just installed them without any torque, their improper stake job didn't even have any kind of resistance when I removed the screws.
I'm not sure if their current production's staking have improved, maybe some members would chime in here about it, if they improved their staking then they should be fine.
Maybe look at getting something else like LMT, Spikes, Daniel Defense, LaRue, Thunderbolt by GTS/ Rainier Arms, or just wait until the BCM is back in stock, you could have Bravo Co. send you an e-mail when they're available.