Big fan of this place. Have been a couple of times since Lava Lagoon launched. A bit like Gumbuya World's lazy river, it has a 'rapids' section with a wave machine about halfway through (in the blurb on the website they mention this). Unfortunately (not sure if by accident or design) this effect only seems to be on intermittently, and without it the current can be so slow you don't really move much. Otherwise it looks really good though, will be even better once the trees start to mature and it gets a nice jungle feel.
Agree that the theming on the bumper cars is awesome.