G6 Real Doesn't have full download play yet , which M3 Real has..
so if you want Download play, go for M3!
also, if you want more memory take the M3.
but if it was up to me, I would take another cart completly..
Like, AceKard R.P.G or CycloDS EVO, or maybe DSTT (not sure about that tho) I've been quite dissapointed at the G6 / team