We have the Best Buy house brand "Insignia" 19" TV and it actually runs on 12VDC as noted in an earlier post. I don't know what the allure of Wall Warts (and external Power Bricks) is, but in the case of RVing it plays in our favor. Just get an adapter and plug in.
We found that across the entry-level LCD TV's, Picture Quality was more equal than Sound Quality. A number of inexpensive off-brands had sound that was weak, tinny, or distorted. And we aren't audiophiles, the sound was just poor. Insignia stood above those cheapies, and it took a higher line like Vizio to match it. And they were a much higher price. Insignia's available on sale at $99 and they sometimes have Open Box deals on them. They have the VESA mounting pattern and even come with the metric screws.