I bought an 80l Techni Ice in January (2010) for camping trips, after a fishing charter and 2 nights of boozing i was out of ice, and i used block ice. a friend had a Engel with a battery pack; his beer was much colder than mine and his wasn't dripping every time he pulled one out. 3 weeks later i had a 40l Engel and i couldn't be happier with it.
with a fridge you do need to be careful though; i had nothing but beer in it and hit the beach. driving at about 50Kph when i hit a dip, Nav got some good lift; my brother without seatbelt hit the roof, HARD. when we got to our fishing spot i realised 2 beer bottles in the Engel had smashed and completely vaporised into tiny glass shards everywhere. Beer and broken glass in a new Engel behind the condenser has a way of making you have a bad day. Had to empty it and hose it out warming it and my beer up. might not have happened in an ice filled box.
Anyway, thought i'd share my first bad experience.