We've had a Coleman one for years and it has worked well. However it has a fan that can be annoying. It was great in the back of our minivan while traveling (there was a 12V outlet back there), but I wouldn't want it in the backseat for anything other than short trips.
Also we used it in motel rooms and would make sure it was located in the bathroom because of the fan.
Maybe they've gotten better, but thought you should know the downside. Also this style makes this inside of the unit about 20-degress cooler than the outside air.