You'll only get a 1 year warranty from a new trailer, and that warranty is only good at the dealer you purchased from. All others will either flat out refuse to help you, or will make you wait a month or more before they will even look at your issue. I don't know if that matters to you or not, but it's something to consider.
I wouldn't worry about the 2017 being used. It isn't more likely to have issues than the new ones. Just take your time looking at them and make sure there aren't any significant problems before purchase.
33 feet might seem like overkill, but I'm a single guy and have a 37 footer. It's comfortable, but I don't think it's overkill. Sure I could get away with less, but I'd need a much different floorplan to have the things I want in it. (I like having a full size washer and dryer. It's awesome to be able to do laundry quickly and efficiently any time I need to)
2014 F350 DRW 6.7L CC FX4 King Ranch Ruby Red Metallic 158,000 Miles 4,450 Hours
2018 Cherokee Grey Wolf 29TE | Because I'm home, no matter where I am.
2018 Honda CB650F | Because the truck leans the wrong way when I turn.