We had a 5- or 6-year-old Norcold in our SOB and a 5-year-old Dometic in the 310. We swapped them before we sold the SOB since we liked the Norcold so much better.
The Dometic was larger on the outside but smaller on the inside, and the Norcold had a light in the fridge where the Dometic did not.
There was a freezer plate of some sort in the middle of the Dometic fridge where the Norcold was wholly open.
The Norcold had a status panel on the front while the Dometic did not.
I don't know if some/all of this can be attributed to the respective models of the two fridges (options vs. bare-bones) -- I don't have the model numbers here to look up, sorry. I can tell you we are very pleased with the Norcold and, if necessary, would buy another one in a heartbeat!
Susan