I love the Wanderlei vs. tomato can fights, haha. Comedy at it's height. As for Wanderlei's issues with good fighters, I think his problem with Arona is pace, and he can't get distance to strike, crocop outweighed him by a considerable amount, and he killed Saku multiple times. Look at Wanderlei v Rampage- he killed him, and Rampage beat the UFC's golden boy, Liddell.
Fedor's a beast, and has beaten all comers, though Zulu was just for fun.