I've been watching it. I don't like that the focus is on whether the fish eats people or not, because I really don't care. That's what keeps the majority of people interested though. They also have the obnoxious camera-waving-everywhere stuff, which really annoys me. I guess it is supposed to add drama, but its just stupid and makes it difficult to see the fish.
The payara in the piranha episode was really cool.
Worth watching, overall.
I saw a great documentary about african tiger fish a few months ago. It also had some footage of a lot of other african oddball fish - bichirs, ctenopomas, elephant noses, etc.