The model you're looking at is the Vista (was Visa) line. I have a 23BHD, but the layout is not discontinued. They added a couple more dual axle options though.
Quality and durability are very good considering everything is made to be light. Nothing is cheap per say. Gulfstream does as well a job as any other in the average...even above average list.
The single axle versions (19 footers) did have axle bending problems a couple years back. If you're buying new, you're fine. They had a spec axle in there that was very close to the actual weight of the unit, and IMO those with issued were also using a WDH, which added some weight to the trailer axle, not helping the problem. But again, they beefed up the axle a little and it has a higher spec now. Should be all clear.