As Bobhenry posted earlier, a mini fridge will use 1.2A at 120V. That's 12 amps at 12V. Figure a 50% duty cycle and that's 6 amp-hrs for a mini-fridge versus 0.5 amp-hrs for a Waeco (they were bought by Dometic so I guess they aren't Waecos anymore). So they really do work that much better.
Bruce