Mancini was pretty damn big for a lightweight. I suspect that if he was around today, he'd come into ring weighing 145-150. I'd take him over Rios, probably by late stoppage.
Mancini, easily. Its worth pointing out that much like the aforementioned* Sanchez with Azumah Nelson, the sheer effort and distance Arguello had to go to do a number on Mancini speaks highly of him of a fighter. I like Mancini, just on that showing vs Arguello alone. ____________ *in a different thread/forum