jay83

go for the g&g

I wouldn't recommend it, I've got a CYMA M4 myself and they're not supposed to be very good internally. Mine is old TM spec so upgrading is limited (idk about the version you are looking at) and G&G internals are probably better. It cost me ~ £140, polymer receiver, aluminium RIS, crane stock. In hindsight I would have rather bought the CM for the same price or the M4A1 for £120

Externals are complete wank in my experiences and the gearbox is no where near as good as JG. That said the hop up units are decent but depends on the QC. A wombat machine or a JG m4 are better options.