Buy it!!! It's cheap ($29.99) with really pretty underwater graphics and lots to do including scaveging quests and fish photography. It's kind of a niche title, but if you liked Pokemon Snap at all you will probably like this. Especially to my Crossers, I think they will really like it. It's as addictive to me as Gallop Racer was.
I wish our 2nd ps2 would come soon because I want to play it some more actually. Brian is playing Breath of Fire, Jesse is playing Xenosaga, and Robyn is playing the Sims so unfortunately there is much sharing. I feel like a brat!