I'll give the edge to Mosley. He was a beast at 135. Pac only had one fight and it was against a mediocre opponent.
Most people will say Mosley, and that's only to be expected because he had a dominant reign there whereas Pac only had one fight, but if we are talking strictly h2h, I go with Pac. I think the Mosley of 2000 beats the welterweight Pacquiao, because Shane would hold significant advantages in weight and strength there, but if Shane had to keep his weight down to 135 I'd back Pac to upset him. Manny looked supernatural at 135 and 140, it would take special fighters to beat him, and Mosley was excellent but not special the way that someone like Pernell Whitaker was special. How would Mosley do against someone even faster than him (similar handspeed but faster feet)? Not too well I don't think. Pacquiao outspeeds him to a UD in a very, very competitive and possibly even epic fight.
