TLC vs. Almost new
If you''re buying a boat that you will keep for a long time, then a new boat will provide trouble-free service for many years, and you can amortize the depreciation over a long period, making a new boat, by far, the better way to go.
If you are more likely to sell within a shorter period of time, then buy a used boat, on which the original owner has taken the big depreciation that occurs in the first few years. If the boat isn''t too old, it will still provide several years of relatively trouble-free service, and still be in reasonably good condition when you sell it after a few years.