Compare the load ratings and construction. It's always better to get one rated for higher than what you need now, because you never know what you'll be hauling later.
I don't know about the title laws in your state, but around here if you buy used you need to make sure it comes with a title before you agree to buy it. Untitled trailers in New England can be a real headache to get a registration for. Sometimes it isn't even possible because of the hoops you need to jump through. Don't count on the previous owner helping you out, once they cash your check, they don't know you any more. I learned all this the hard way and ended up having to scrap a good trailer because it was easier.
I looked at the HF, as well as ones offered at HD and TSC. In the end I chose to buy a 5x8 beavertail made by Belmont (made in Amish country) from a trailer dealer because it used a better axel, and was constructed better. I've had it for 5yrs and am very happy with it.