Since the flyer nerf v1 (don't know about v2) these are probably one of the best ways to get around the island. On four legs, these things are probably faster than anything that's not a Gallimimus, and they have no stamina drain, if not it drains very slowly. On two legs they have a decent jump, but no matter what they have decent weight, health, and ok damage. And since their saddle is cheap and low level, they can be used very early in the game.
Iguanodon is a very useful dino. Its strong, fast, have a lot of stamina, can jump really high, can collect a ton of berries, can turn it to seeds, when u need, and poop for u big eggs. :D A must-have creature in the game.