My opinion--yours may vary:
If one gets either a 12 or 120 volt only fridge the small batteries typically used OEM may not be enough for your camping style (depending on disconnected time.) Additional batteries may be necessary even for the 12 volt only. Adding a 120 volt residential does require adding an inverter--that is what we got OEM in our fifth wheel and we love it. The Everchill brand of 12 volt compressor fridge is being used frequently now by Forest River brands (saves the cost of the inverter.) However, 2 folks with brand new trailers where we camped in January were having trouble with them. One noisy as all get out and the other tripping out so as unusable. I wouldn't touch an Everchill, myself.