I don't think the term "better" is appropriate in this context. If we ask what specific fighter could gain the most benefit from which trainer that would be appropriate. They are all great trainers, but not all will get the same results from a specific fighter.
Steward, Virgil Hill, Floyd Snr, Nacho, Robert Mc kracken Gamboa's Dad and Stephan Larouche Bute's trainer. Naazim Richerdson, Uncle Roger.... ( Buddy Mcgrit...baby ....lol just kidding)
EPO is the better trainer. Pac, Mosley, Hopkins are all on the EPO "juice", and when you're on EPO, you can add Anabolic Steroids, HGH, Clear Cream, and other PED's, to the mix and you'll be almost impossible to beat, regardless how skillfull, how out-of shape youre in, cause those PED's will compensate for all your flaws. but EPO, is the main and startimg PED.