I don't particularly like Hernandez either, but the way Villone has been pitching lately I'd say he's probably more reliable then him. Now I'm not clear on the "roles" in the Yankees pen, but Hernandez is essentially the last guy in the Mets pen and you're comparing him to 2 guys that have logged 22+ IP the last month with the Yankees.
I'm hopeful w/ our division race over that joe rests some guys down the stretch and has their arms fresh for october.
