G&G CM16s are good quality, even for polymer receivers, etc. Even the RIS unit is polymer, but you would be hard pressed to tell, except for the lack of weight.
As regards TeddyBhoys problem, the wires from the gearbox to the battery run through a couple of speaker type spade connectors to keep the size down to run through the stock tube, so they probably pulled apart when the top part got stuck. It's a fairly easy fix, once you remove the stock tube, to push the connections back together.