@RandomM_YT My nephew has the G&G Armament Combat Machine CM16 FFR A2 and I'd say for the year and half or so he's had it, and with it costing around £230 currently, I'd not buy one.
It's been back to Patrol Base once, for either a faulty ETU or MOSFET, however they never said what the fault was but it came back working again. Generally considering the cost of one the weak points for me are the bang average geared hop unit, the fuse takes up masses of room in the buffer tube restricting battery space, the hand guard has unusually sized screws for mounting rails (no M-LOK etc.), and in general there are much better rifles from other brands for at least £50 less.