We have a Samsung 10 that we really love. We originally purchased a Mintek 7, but the battery kept getting super hot (dangerously hot). The battery was located on the bottom, so you couldnt put it on your lap. The Samsungs battery is located in the rear of the unit (no heat problems either) and the picture is awesome. Sound is okay, but it does project a surround sound even with the two small speakers. We rarely use the speakers anyway, mostly headphones. The Samsung is really thin, so this unit isn't too big with such a big screen. Our main use for the DVD player is on planes or connected to the TV in hotel rooms.
The battery is only good for one movie, but most planes have a power port. I do have a back-up battery for the long trips where a power port isnt available.
Portable DVD players definitely make those long plane trips go by faster.