Hi Simmons.. you don't mention which model of Damon you are considering, but since our experience was with a 2001 Intruder 36' gas model,,here's our two cents worth.....It was a great unit for the money we spent. We had no issues with it, but we only had it for a year. And Damon was very supportive with technical questions etc. It was very much on par with most of the other 36' gas models at the time. Now, many people seem to have negative comments about Damon in general, I guess they had some problems. It probably is not built to be a fulltiming rig; the cabinets are chipcore, fixtures are not heavy duty etc. But for our experience, we got more than our money's worth in the unit. I don't know too much about Gulfstream, but from the few I've been in, the construction seems similar to the Intruder.
I don't know what your price range is, but if you can, consider looking at an older, well made diesel MH. Lot's of people bad mouth the Monaco products, but we've had several and they were built like tanks. The Windsor was a really well made MH for the $$$ and you can probably find some good deals on '99, and 2000 year units. Also in Newmar, the DutchStar is a great value and well made MH. Tiffins are supposed to be great also, but they are hard to come by in a good used unit.
I'm sure there are lots of other folks who can give you an opinion also. Hope this helps you some. Whatever you buy, be sure to check out the CCC (Carrying Capacity) before you buy it.
Good luck and enjoy the search.