Roach. Not only for what he has done with Pacquaio, but look at james Toney under Roach and how he cleaned up/sharpened Tyson's skills when he was with him. Both are top notch trainers
I'll say the outcome of the fight might determine whos the better trainer...than again pac is a better fighter than hatton so if hatton wins convincingly and depending on how he wins (does he look good...did he shut him out...is he using a certain gameplan mayweather sr came up with, etc...) than you could easily argue mayweather sr is the better trainer!
Roach didnt do anything for Oscar when he fought floyd and Oscar went back to Mayweather sr. :deal and wlad klitschko left Roach for Emmanuel Stewart
and Dawson left Sr and won a title. Jr left Sr and won multiple titles and Guzman came in overweight with Sr. The fact of the matter is, trainers fit certain fighters and not others.