There has been a ton of hype and a ton of exposition on this "mega" fight, so I'll make this short and sweet.
Oscar de la Hoya may have the edge in experience and possibly strength, but he is going past his prime and has had a history of difficulty against quicker, more agile opponents. Floyd Mayweather Jr. is just that type of fighter and much more, as he also possesses a great set of both physical and mental skills. His one, rather major strike--he rarely fights anyone within breathing distance of this abilities nor has he fought anyone that could really challenge him. Is the Golden Boy that type of guy?
If one went by his last fight, against Ricardo Mayorga, then that question just might remain as one. Sure he TKO'd him bad, but he got tagged far too many times by the lesser skilled brawler. Pretty Boy Floyd seems all wrong, but at the same time, he hasn't had a good elite-level opponent in ages, even if that person is relatively inactive and fading away.
In the end, PBF will still be too much for ODH to handle, despite the motivation to shut his big mouth up.
Prediction: Mayweather, KO--Rd 8, or sooner than that (nothing early, though)