What level?

Mayweather is way above Williams, Margarito, Cotto, Mosley at their current rate.
Now that he is gone there is no real great fighter left in the WW division hence why the lightweight is better now. Williams left the division as well.

I think Mosley is the perfect opponent for Berto, he can't throw anything effectively except that right hook from everything Ih ave seen, and Berto can block that all night, also if Cotto was landing his jab on Mosley with ease, Berto has just as sharp of a jab, but its twice as fast. Once against only Margarito as of right now I have any hesitation of Berto beating, but you guys will see after the Collazo fight whats, what.

I see no similarities between Julio and Berto, Berto is fast, defensive oriented fighter who has the power and speed to knock guys out. Julio is a purely offensive minded fighter who is skilled ,but doesn't have the physical tools or skills developed to be a top level fighter. I think Julio would have had a lot of trouble with Forbes.