12 v. TV's are much more expensive than 120 v. ones. They claim the ones made for RV's can take the shock of travel better, but our cheap TV in the bedroom has survived quite well; the OEM TV has too and I doubt it was made for RV's since it is a 120 v. model. If you need TV when boondocking, you can use an inverter to watch a 120 v. TV, but batteries can be run down if you are running the furnace and a lot of incandescent lights. We have a small 120 v. cheap TV in the bedroom plus a separate inverter, but we have used it infrequently.
If you want a TV with a DVD player, remember when one stops working, you need to replace the whole thing. Our trailer has a 12 v. radio/DVD player that connects to the main TV, but when boondocking, we survive quite well with CD's or radio or reading.