For that price range I'd go for a Tippman A5.
Runs on HPA or CO2
Reliable as hell! Plenty fast w/ the stock trigger, scarry fast w/ the Response Trigger....although that turns it into a gas hog real quick!
VM68 will serve you fine at castle though. Definately fast enough.
Although you've GOT to have at least one backup at EMR...I LOVE that place, but it's the bermuda triangle of paintball guns!
...At Grail this spring, I chronoed two guns in the back yard, packed them up and left for EMR 1 hour later. Got to EMR and they were both leaking!
Strive for that moment when you're only a slice of pizza and a hooker away from paradise.