Pdave,
Honestly, you won't go wrong with any of the 3.
With that said, the M2 comes w/ the comfortech, synthetic stock which will take some field abuse & not show it as much as the Monty or the Ultralight. The ultralight stock has had a "weather tech" finish applied to the wood which helps it shed water more easily, but slight dings & scapes will show up just like on a high-gloss finish gun.
If you are in a state that does not have a shell limit, I'd go with either the Monty (if you prefer wood) or the M2 (synthetic, camo). But either of the 3 make for an awesome bird gun!