Floyd and Roy are the only two on that list I'd argue ahead of Manny though, even as much as I got love for Hopkins.Hard to say overall, because you're talking about mixing a bunch of weight classes.
Keep in mind that in the last 20-25 years we've seen some great careers:
Floyd Mayweather Jr.
Roy Jones Jr.
Manny Pacquiao
Miguel Cotto
Juan Manuel Marquez
Oscar de la Hoya
Bernard Hopkins...just to name a few
To call Manny a top 15 or top 25 fighter all-time...given the long history of boxing...that might be a stretch.
Not saying he isn't. Maybe he is. But the guys who said Top 50 seem more reasonable....at least at 1st glance.
I mean, Top 50 goes without saying.