Aside from being more powerful, Broly's speed also increases when he becomes LSSJ(the added bulk doesn't hinder him in the slightest.) Trunks, on the other hand, takes a massive decrease in speed when he becomes USSJ.
STI
StiltmanFTWCBvF
Yeah, Broly wins this.
SSJ
SSJGGogetaSenior Member
Trunks would still be a lot weaker than Broly, in USSJ. He's just too strong. And Trunks loses a ton of mobility, and combat speed, when he goes USSJ. Broly take a massive INCREASE in mobility and speed.