Super Trunks would win cuz yes he slow but hes stronge meaning he wont be as fast but he doesnt need to be . If i recal correctly super trunks was twice as stronge then super Vegeta , so I believe the battle would be like super Vegeta vs Cell . Remember super trunks was almost as stronge as perfect Cell and super Vegeta didnt stand a chance and cell never moved cuz he didnt need to.
It's really all just circumstantial. If Trunks just stood there and waited for Vegeta to attack, then attacked, he'd win for sure. Beam struggles, Trunks would win. But, if Trunks rushed stupidly at Vegeta all the time, Vegeta would win
Super Vegeta all the way. Because Vegeta is always training and well Which Trunks are we talking about? Small Trunks or Future trunks. Any way either way Vegeta becasue Future Trunks really doesnt have anything to train for/train with.
Super-Vegeta would win. When fighting perfect cell, he said he did not want to go as far as Trunks, because he knew that he would be too slow. He is far more experienced. But i have to say he is not better than goku. I would appreciate. But goku is always better, but nobody knows why. They explain it the way, that goku is a kind of genius. That really sucks. Vegeta is much more determined.
thing to remember is that in hand to hand combat is speed is always better than power. The only time this reverses is when the strong opponent is to the point where the weaker opponent cant actually dish out any dmg also taking into account the energy blasts in dragonball z vegeta would be able to use these on trunks far easier than the other way round.
Sorry but vegeta kicks trunks' ass in the episode where he goes to super saiyen 1.5 to let Cell in his 2nd form get to android 18 with not the slightest care that he is his son, but even at that time when vegeta was letting his pride possibly doom them all trunks was still reluctant to stop him cos he is his father.