Tahm Kench is the best pick for Top Laners
Tahm Kench is not only the King of the River but also the King of Top lane. The last few updates boosted this champion so high, that no one could stand against him. Or those who try will face an inevitable defeat, due to the unexpected survivability from Tahm and good damage dealing abilities. In the current League of Legends meta, he is the best tank, that can carry the whole team straight to the victory screen, so he is the best choice for Elo Boosting. Glory to Riot Games for shifting his utility abilities into a RAW POWER that giving him an ability to smite opponents.
Even if you like to build your champions into a full-tank mode, Kench will still be able to outduel such monsters as Renekton in the early game and laning stage. His power and potential are fully open with the dueling melee champions. I have seen with my own eyes how Tahm Kench won the duel against Fiora in the late game, while he was behind in CS, like for 150 minions. This is the only proof I need to start picking him in any situation!
A few advice from a Challenger
Every TK who wants to dominate the lane must start his match with a Sunfire Cape and then go straight to the defensive boots. Choose such defensive items to dominate at the laning stage, do not look too far in future, trying to outstand the whole enemy team. The next overpowered item on this guy is Titanic Hydra, but only if you are sure that this game is already won and you want to ensure this victory by building some artifacts that will transform you into a Carry.
The only weak point of Tahm Kench is his low teamfight potential. He could be easily outscaled in a pretty short time, but it is not so important. Do you really believe that aggressive top laners, like Renekton or Riven, that are so popular right now, would stay behind and not fight?