When it comes to Real Estate, buying used can be an excellent choice if you're able to find a property that is only a couple of years old and in perfect condition. Otherwise, investing in a new one might make more sense. Do your research and explore all of your options before making a decision!
@Kyler J Sloan based on what others have said about what repairs are needed I would bet on a fairly new used one only for a STR if you were going to get one. I would never have one in a LTR. We personally have one but that came with the house I was surprised to find out its age. Thankfully no repairs yet. To me pools are more useful.
Some of you guys are funny. "Only NEW for MY guests!"
The timing of this question is good. I have been managing vacation rentals in the Smokies since 2005. Yesterday was the very first time that we have recommended purchase of a new tub for an owner: It had a crack in the tub that could not be repaired.
A hot tub is a pretty simple, unsophisticated appliance: You have a shell, a heater, a pump, and one or two circuit boards. Unless you crack the shell, there is never a good reason to replace a hot tub with a new one, as they are quite easy - and cheap - to repair.
A hot tub that has been sat in is no different than a previously-sat-on toilet, indoor bathtub, shower, sinks, or refrigerator. Or how about all those supposedly-cleaned dishes in the cabinets that a thousand people have used? And how about that master bed - do we really want to know what all has happened there? Or those floors you're walking bare foot on. Are you kidding?