I think that 300 euros is too much. It will be sth around 200-240 euros. Dont forget that oponent for g2m willl be moto g (quite similar specs, prop better screen). If g2m will cost 300 euros like u said then Moto G will be way better choice (and much cheaper) and in price of 300 euros u can find better phones.
Devices: Galaxy Ace 2; Galaxy Y