A few points to consider:
1) Floyd does better in rematches, as evidenced in his fight vs Castillo.
2) Floyd is very smart and will insist on a ref who will focus on Maidana and make him less effective by not allowing him to maul.
3) Floyd has seen Maidana for 12 rounds and seemed to figure him out by the later rounds. This doesn't bode well for Marcos.

Maidana will always be tough because he fights aggressively and at a ridiculous pace. He will always tire, not because he isn't in shape but because NO ONE can EVER sustain that pace and physicality for long. Look for Floyd to weather the early storm before coming on strong in the latter half to have Maidana holding on to reach the final bell, or possibly be disqualified. Floyd is just too good and on another level from Maidana. No one at 147 except Manny stands a realistic chance of beating him. Before anyone says or asks, I make Manny the underdog in that fight, but possibly higher ranking historically than Floyd at this point. Tough calls.