I recently ordered the G&G M1903 and although the gun looks and feels nice the internals need some work. The magazines barely fit in the gun correctly aka they are loose and fall just short enough to stop the bbs from loading correctly. The hop up unit cannot be adjusted at all due to the closeness of the wheel and mechanism to the wood body.
If anyone was looking at this I would suggest picking it up because it is incredibly fun when it works, but wait a bit in order for the glorious G&G to work out the kinks.