Both are great tubs. I happen to be a Hot Spring and a Jacuzzi dealer and have those tubs right next to each other. Some basics to keep in mind: The Jacuzzi will be deeper, a lot deeper. Even though the spa is technically 1 inch higher than the Prodigy, the spa seats are lower and there is more open space. This makes the J-325 hold 430 gallons vs. the Prodigy that holds 325 gallons. The J-325 also requires only 15 amps on a 110V circuit, and cost nothing (from the dealer side) to upgrade to a 220V. The Prodigy however requires 20 amps on a 110V, and cost roughly $200-$300 to upgrade to a 220V because Hot Spring makes you use their disconnect box.
Other minor things:
-Jacuzzi has 4 pillows with lights behind them, the Prodigy has no pillows
-Jacuzzi has the waterfall, Prodigy does not.
-Jacuzzi is deeper, Prodigy is fairly shallow.
-Prodigy has a higher transition seat, Jacuzzi's is fairly small and much lower.
-Prodigy has Ozone standard, Jacuzzi does not from the factory (however your dealer may have included this)
-Prodigy has a more intuitive control panel (although I like simplicity,) Jacuzzi has a simple control panel (what else do you need)
-ACE option on the Prodigy
When I have people comparing the two, it almost always comes down to height. My in-laws purchased a Prodigy from me last year due to most of them hovering around the 5' mark.
I could probably think of more, but I would push for them to get the Prodigy in so you can sit in it. Tell them they'll sell it eventually even if you don't buy it!