G&G is easier to work on but the stock is weak. It is it's own gearbox too, nobody else uses it. Mags are also expensive. CA is a clone of the G&G.
With the correct components the g&g works great. The hopup unit is from an AUG.
I futz with V2s, V3s and V6s. I could be wrong... but probably, most likely not, as far as I know.