I have the trailer vision two camera system and its very good and ive not had any problems in the last 3 years with it. i even broke the arial off the monitor ( my fault ) and they sent me a new one for free!
I also have a Trailer Vision camera system, I really like it and haven't had any problems with how it works in the year I have had it, however the suction cup on the monitor will not attach to my windscreen, so although I try to wedge it in a suitable place it often goes flying across the dashboard when I go round a corner (okay a bit of an exaggeration as I drive at sensible speeds round corners, but you get my drift!), and I wish the monitor came with a case for when it is not being used.
We got an excellent one from www.horseboxworld.com through their on line shop which was wireless with Batterys at the Horsebox section end and plugged into the Ciggy lighter at the front, Its colour too.