I don't think there is one answer to the new/used question. I like to consider prospects as they come on merit. Sometimes you find a great deal on something used, but you also might be waiting a long time. And time is the one thing you can't buy more of.
Also, if you plan to finance, rates will usually be better on a new unit, than on a used one. If a used trailer is only 1 or 2 years old, you might get a new one for nearly the same payment.
And watch out for those prices on late model used trailers. Too many people pay too much, finance for too long, and end up needing to ask too much because they are upside down. Make sure they end up paying for their mistake, not you.