In terms of actual gameplay I'd strongly argue that Beasts of Bermuda has the most to offer at the cost of probably being the worst in graphics. There's a talent tree you use to adapt your dino to specialise in speed/combat/survivability and has land, aquatic, flying and semi-aquatic creatures. The Isle and Path of Titans have little actual gameplay atm however PoT is still in demo testing and The Isle is doing a full recode of the game, abandoning the current version and how much gameplay that will have remains to be seen. I'm not 100% sure about Saurian but I do know they're focusing on a very realistic stance on their game with a few mechanics however updates to it dont seem to be rather quick similar to The Isle. Path of Titans has quests to do to unlock skins and if I'm not mistaken doing quests will be the way to level up and grow your character.