This update is gorgeous. On my 24 inch iMac Intel Duo Core, I don't get any of the rendering problems mentioned in a previous review.....I mean, if I look super-close, using a magnifying glass, I can see very, very slight anomalies on the edges of some objects, but I really don't see anything that takes away from my viewing pleasure.
I love the "pan" feature, and the new moving background objects, especially the Christmas Tree Worm and the antler corals.
I love that I can have up to 30 fish on screen a once...looks amazing on my big monitor. The integration with iTunes is way cool and works flawlessly.
I also own and love 3D Aquarium, but the detail and movement of the fish is definitely superior - sharp, crisp, realistic. I see many more artifacts with 3D than with Marine Aquarium, by the way.
Finally, have to say that this new version is so gorgeous is breath-taking. Friends who have looked at it are just blown away by the realism of the look and movement of the fish. This was an upgrade from 2.6 for me, and I think it's worth every penny.
5 stars for sure.
(Oh, and try running this as your desktop with something like Wallsaver. You won't be able to get any work done...you'll just want to watch your desktop!)