I believe Vegeta and Goku cancel each other out.
Which leaves Gohan and Piccolo vs Trunks. Hmmm...I think Trunks has the power advantage, but if Piccolo can take control of the two on one, I think they win it.
Then again, Trunks doesn't wait around to end a fight. If he goes for the kill right away, I give this to Trunks. The longer it goes on, the more Piccolo and Gohan start to take advantage.