TRA is very friendly and knowledgeable about the P6 system, a great resource indeed.
I am a big fan of this system:
If you buy from a reputable seller, camera should not give you any trouble, as long as you follow the instructions carefully. Making sure film is wound tightly, and not letting the advance lever return with full force are the two main considerations when using the camera.
Final units can be identified by the plain release button (all others have engraved circles) and all-metal tripod mount (others have leatherette coverings), so that should ensure you get one of the last cameras. Depending on the sources, there were around 207k or 205k cameras made.
Lenses are all excellent, my favorites are 50 and 180 but all of them are great glasses. The system has plenty of accessories, fresnel screens can be had for about 20 USD, and there are still repairmans out there willing to have a look at our cameras.
Incidentally, I am selling one of the kits (a newer one, #202666) to raise funds for sending the Linhof to a CLA, if you are interested...
http://www.flickr.com/photos/jnoir-photography/sets/72157630032189026/ 