G5 is fine. If you can get 4500 fills at the tournaments you should be fine. If not I wouldn't go with the G5.
Any of the new guns on the market will work fine if you just take care of them. Or you can buy an older used gun and get something way cooler for the same price.
ETEK 3LT, with 14" Ti boomstick and cure 3 + bolt F/S
Vanguard creed eyes, membrane, bolt pin, detents, gaskets, schraders, orings and more F/s[/color]
Old school angel poppets/cup seals(LCD and A4/speed), spring detents(not sure which models) F/S