If you look at the lines, I would say the J365 fits between 2 models . 1 Nautique,, 84x 84. 2. Nautilus 92x 92. Both are very good tubs. Both use the 24/7 circ pump, both have ozone. The D1 system uses a 3 chamber ozone that does not offgas into the main body of water,, Both have 2 main pumps,2 filters,both with headrests in the corner seats, the D1 are adjustable with neck jets, Jacuuzi spa standard with waterfall, the D1s are optional with the LFX package. Both warranties are about the same,,, Both are very good lines, @ of the first modern spa manufacturers in the industry......