To be honest, It depends on how you want to use your fridge. In my case, my Danbury is classified as a 'Day Van'. In as much it is more like a Bus layout but with the option of setting up for sleeping. All the storage and cooker are housed in the seat boxes. When camping, we usually have an awning so we use an old Electrolux chest fridge and run it on gas. While travelling it can be plugged into the 12 Volts or if at a serviced site it can be plugged into the mains.
If you want to have a built-in unit, then there are options of a compressor fridge or gas. Clearly, as the name implies a compressor fridge will have a motor running. This will be a bit noisy compared to a gas fridge which is pretty much silent. Also, I think I'm right in saying that you can only run this with electrical power so would need to be powered from the camper or mains hook-up.