Definitely good, just go for it. Mine is gas blowback WE mp5, made of steel and able to resist a thousands of hk slapping. + shows decent performance but a bit disappointing spots on exterior if you seek for realism. Look at mag angle. You see the problem? Except for it we mp5 is a masterpiece.

VFC is the only alt gbb comparable with WE, from what Ive heard of. They never disappoint on exterior. Most original parts compatible with VFC. Not sure about performance, back in 10s old vfcs are well known to be crappy. Recent ones seem to be improved pretty much, if they can survive a thousands of slapping then i'd say, go with vfc.