Journey to Atlantis is far from the best water ride or roller coaster on the planet, but its combination of the two makes it an enjoyable and fun ride. The exterior architecture of the building is quite impressive, but I found the interior theming rather disappointing. There are very few effects, and the scenes are too dimly lit to provide any clarity as to what they are. There is supposed to be some kind of storytelling, but I'm not quite sure what it is. You are supposed to follow some kind of light through various scenes, and close to the end of the ride Medusa swears revenge, then all of a sudden you a plunged down the final drop!
While the theming is far from spectacular, the drops on the ride are actually good. The first drop is quite steep but aside from a bit of spray I didn't get very wet. The second drop is so small you'd hardly notice it, but it absolutely drenches riders in the front of the boat as a wall of water spills over the front. The final drop is the coaster drop and this comes as quite a surprise, it features some good laterals and seems quite fast, and produces a little splash.
Overall, Atlantis is a fun ride, but could have been more exciting with better theming.