There might be a long list of disappointed Gufstream owners on this forum but I also heard the same complaints about every other Manufacturer since I've read posts here over the last 6 years.
I bought my 07 new and have never had a problem with my unit. I have had it serviced to manufactures schedule and I tinker and tighten screws every chance I get (standard procedure on any unit). Gufstream has never had a good reputation for customer service but my dealer has treated me like gold on any Major problem I might have encountered over the years.
Gulfstream no longer builds a class A unit but at least they didn't bankrupt the company to get out of covering existing warranties like many other companies did back in 07 & 08 only to leave the owners high and dry and on their own and the company start back up with no issues.
If you like the unit and floor plan and the price is right for you then I would recommend you purchase it.
Take the advice of the earlier poster and go to irv2.net and read the posts made by other owners. Its a lot better than listening to the "my brother had a cousin that new a guy that had a friend that stayed next to a guy that had a brother that was in prison with a guy that owned a Gulfstream.