Ricket if you buy new from a major reputable manufacturer you will have at least a five year warranty which is a lot of peace of mind.
When I started out to buy a hot tub I too looked at used however I soon realized that most used tubs were over priced considering the risk I was taking in getting a leaker or having to replace motor/pumps, heaters, and electronics.
The older the tub the greater chance for leaks from the stress of moving it.
I must say thought it was a good exercise, as I learned a lot about hot tubs relative to the cost of replacing the above mentioned items and my conversations with repair people who pointed out the problems with old tubs.
Let us know what you decide.
Regards, Zz