So I tamed an iguanodon fairly early on in my current play of the game. I always level health high and then speed. I started to realize just how fast she was and how tanky she got. I started leveling damage and weight. As of now I can easily tank rex attacks and beat alpha carnos. I haven’t found an alpha rex yet but I’m hunting. I can also run the entire map in half the time an argentavis can fly it. I’m starting to level oxygen so that we can just ruin anything and everything. If you take the time and level them really well, I think they could be giga killers but at least really good at traveling especially given the smaller size compared to most tanks. The fact that they don’t have to use stamina, and are faster if they don’t, is definitely a plus. Combine that with the fact that they have a very vertical jump and you can scale the steepest of mountains in a few minutes.

TLDR: take your time and level them right and you’ll have one of the best mounts in the game for traveling or otherwise.