I have fought through the Cell Games and won with Broly, Bojack, Cooler, USSJ Trunks, Great Ape (which took a LONG time), and Great Ape (Vegeta). Here is who I think the best and worst of these characters to use in a WT are.
Worst- Great Ape: why? because he is VERY slow. Even when GA is trying to pull off a combo, you can still dodge it because he moves that slow. His attacks also require a lot of Ki to use and GA simply does not have the time to charge up.
Best- USSJ Trunks: why? Because he is the perfect size. He can easily tangle with the big fellows while still being able to handle the little ones. His attacks and devastating and do not require tons of Ki.
There you have it. My personal take on all the "Big" guys. What are your thoughts?
I'm a big DBZ fan. Some of my favorite characters are Vegeta, Cell, Janemba and definately Trunks. I am a moderator for the Budokai Tenkaichi forums.