What tow vehicle do you have? That's the question everyone will ask. Lots of threads about that. Read a lot before you settle on a truck if you don't already have one. If you do, that will dictate a lot about the new trailer. Dealers are not the people to ask about this in my opinion.
As for a used trailer, that's the way to go in my mind. A lot of people buy one, it sits for a year or two not used, then they trade it in. More value for your dollar that way. Some will disagree and talk about warranty. That's a valid consideration. Personal choice