Unless you are out in pretty cold conditions (like below -10°F or so) the biggest advantage to insulated is that you don't get condensation inside like you do with a non insulated house, especially if it is snowing or sleeting out. If you're fishing a lot of days it snows a lot, it would be worth the 100 bucks not to get dripped on imho.
You'll also burn less fuel if you run heat with the insulated, so it'll pay for itself over time if you heat.