Generally digital ones will be much more accurate and precise. If the particular air conditioner system used in the RV doesn't require a proprietary thermostat, most any digital one that can be powered by batteries will work fine. A thermostat that relies on the furnace or air conditioner for power may not work in an RV since household HVAC systems use 24V AC power rather than 12V (or occasionally less) DC power as is used in RVs.
You can read about my thermostat replacement (and some other things) in
this thread. (The exact model of thermostat I used seems to only be available for prime members at the moment on Amazon.)