I disagree. Mayweather is a product of both them, and he was far from a complete fighter when he was just with his father - he was more offensive minded, but his defense and his ring generalship was nowhere near what it is today. Floyd fights EXACTLY like Roger. Creepily so.
As far as padwork goes, Roach doesn't do anything different than most other trainers I know (or even much different than my own does.) It's pretty simple stuff because boxing, at the surface, is not a complicated sport.
The Mayweather style (Floyd Sr. tends to do the same thing, watch him do pads with Ricky Hatton) is kind of a different animal. There's a lot of patterns in there - it's not just slapping at the pads - and there's a lot of slipping and ducking and blocking, which is often lacking in more traditional padwork. My best guess is that it makes defense and offense blend much more efficiently and eliminates the differences between them.
Roger kind of has an easy job with Floyd. He's said that he doesn't tell him how many rounds to do on a given day, or how much to run, and that Floyd is pretty much the ultimate self-motivator. However, be careful to rob him of credit. Floyd without Roger is not the same fighter, for whatever reason.
And look at the quality guys that Floyd Sr. has trained - there are many - and I've got to believe their style is pretty good. They both were good fighters (Roger was better) and they truly know the game inside and out.
As far as Freddie goes, I can't say honestly that I'm a fan of his but he also knows the game. He's taken several fighters that were good but lacking in key areas and made them into more complete fighters - Pac and Khan come to mind.
I wouldn't say he's overrated. I'd just say he comes off as a doucher. But I've never met him, so I can't say for sure.