Saw it last night. The original is a family favorite, so take this with a grain of salt.
We loved it. Had different opinions on it re: if it was better than the original, but the visuals (as expected) were simply amazing. Storyline was similar to the last one, also as expected, but I liked how they didn't change the characters' personalities. For example, change the main female character into an over-protective mother hen or the main character into a tree-hugging pansey. They maintain their battle-tested roots, and they're gonna need it, because there's a LOT of action sequences. Some new animals that we loved, not-so-subtle jabs at whaling and other "ecoterrorism" type stuff, but not any more so than the first movie.
TL;DR it's really good, visuals are amazing, storyline is similar. Would fully recommend if you liked the first one.