Hi Marvin,
Yes we bought an 05 Discovery, 39J model, when it was new, back in October 2004. We now have about 32K miles on it and we just really do enjoy it. We had 5 or 6 little minor adjustment issues just after we picked it up, but other than that we really have not had any problems whatsoever. We have made several cross country trips and it has performed flawlessly. I would say that we have probably towed a vehicle at least 30K miles and that Cat 330 pulls a 5,000 vehicle with ease. Granted that we have not done a lot of mountain driving but it does very well in moderate hilly areas.
Ours has 3 slideouts and has the booth instead of the table. We have not had any system problems at all. When we were looking it seemed like the Discovery gave us the overall best bang for our dollar.

Send me a private message if you have any specific questions. I'd be more than happy to assist you if I can.
Larry