I'd C/R the flop. He's not checking through. With your line I'd 3 bet and call a cap, then bet / call the turn and go to showdown unless it comes two back to me at some point. He's a semi-maniac, his range is big, and your hand is likely best. With two other players chasing along there's no concievable excuse: get more money in the pot.

Also, a note on the cost of being out of position and ramming for value: The problem with being out of position is that it basically forces us to make more mistakes in terms of the theory of poker, since we'll always have less information. We also have less options in the lines we can take, etc. Some of these "mistakes" we have to make, but there are others that we don't. Learning to play out of position is important (playing the button is often a cakewalk). You'll never do as well OOP as on the button, but (particularly against low-middlish opponents who don't do the utmost to abuse their position) the better you play the less of a value gap there is between the two.