Turtwig, Chimchar or Piplup for Pokemon Platinum?

Chimchar if you want the easiest run. Infernape hits fast and hard and covers Roark, Gardenia, Byron and Candice, plus half of Cynthia's team. Piplup is the safest pick though, Empoleon's typing means almost nothing in Sinnoh threatens it. Turtwig is the one I'd skip on a first run, Torterra is lovely but it's slow and the fire and ice gyms are rough on it.