This is interesting stuff. Where do you recommend buying thi s equipment?
Since we buy new we have shopped reputable dealers. Since what we wanted was small and self-contained we were able to find a dealer with something suitable already on the lot that he was having trouble unloading, so we got it at a good price.
The trick is to research the manufacturers on the net, first, to find out which have a track record of producing good products.
It's been a while since we last bought one, so our research is out of date and you'll have to do your own. There is some turnover in the industry, so a company that is good for decades may cheapen their product, merge, or go out of business.
Our current one is by Sunnybrook, which has since merged into another company. (Pity: They did great trailers with solid aluminum framing, great layouts, and high quality throughout. Only problem was the imported tires - which we replaced with Goodyears after a few thousand miles.)
Before that we had a Prowler from Fleetwood, which has since gone out of business. (They had had a great rep, but our instance, and others from their last few years, had issues with water leakage.)