The Engel Fridge Freezers are very efficient, and reasonably priced. I've got one in my RV and it's treated me great thus far. No complaints at all.
I am using a Nova Kool compressor fridge in our FWC. It was almost a direct swap out for the Norcold 3 way. Nova Kool offers a bunch of different sizes. They are more marketed to the marine users but they work just as well in a RV. I love having better temp control, able to use it in all type of angles (unlike a 3 way) and is much more energy efficent. http://www.novakool.com/
They are also a little cheaper in price than an Engel too.
Once we get the teardrop finished, this Norcold DE-0751 is the fridge we have for it. It's a marine unit, with the same compressor as the chest units that Norcold sells. Haven't tried it out on 12V yet, but it works well on 120.