I'd actually lean the other way, and not because of the extra innings (which could be more than 20). I actually wouldn't expect Melendez to be the better pitcher, inning for inning. He's younger, but not (IMO) better.
Oh, and unless this is the most pitcher dead World in history, I sincerely hope having the money to go "all in" on either of these guys does not mean you are anywhere near considering a max deal.