Phantom of the Abyss all the way, it can just dodge half a battle.
Though dragon is my fav splinter - mostly because of how they have a good mix of melee, magic, and range + can be used with other splinters. So if I have a monster thats good for a particular ruleset, i can go with some strong Dragon monsters + whichever other splinter for that particular monster.
username: @jondoer