Marquez. He can lead with it, counter with it, use both hands for the uppercut, throw it in the middle of a combo, or finish a combo with it.
Those Marquez uppercut are impressive. They are quick and thrown in combination. Bute's uppercut is more powerfull though. I do not know which one is best but I would tend to say it is Bute's. Mr.Troll... great name!
I know a good HW that has great uppercut that he almost KOd himself. He's Britain's greatest last hope.