My favorite Splinter is the Water one, so I have played a lot with it, I'm also a newbie, right now I'm in silver 2, after reaching gold 3. I can say I don't like those tanks like goblin mech, but I have to accept that these cards wins a lot of matches in the early leagues, so they are very strong. I really like cards that make pressure because of their effects, not stats, and that's why I have decanted for the Ruler of the Sea card, the 3 magic damage (+1 thanks the default water splinter), the blast ability that makes it a threat not only for the tank, also for the second place (and other positions depending of the rules). Kraken is a very strong card, but if the enemy has magic damage or the Ruler of the Seas, in 2 or 3 turns it will be no more in the match. So I select Ruler of the Seas.