No one is better, they are all strong, you can pick any one you like, it doesn`t matter.
They all have strenths and weaknesses.
in order from best starter to worse Piplup Turtwig Chimchar
Turtwig (grass) Chimchar (fire) Piplup (water)
You can only get one of these starters in Pokemon platinum: piplup, chimchar, or turtwig. In my opinion it is best to get piplup for type advantage. Example: if you get chimchar your friend (on the game) will get piplup, and chimchar is fire so piplup will win because it is water. Same thing with turtwig, he will get chimchar and grass is weak against fire. But with piplup, piplups only weakness is electricity and niether chimchar, or turtwig is electricity so piplup is your best bet.There is a cheat to get all three of them but I don't know it so the only way you can get piplup if you already have chimchar is to trade with someone who has piplup.
you can start of with chimchar piplup or turtwig piplup would be the worst because its third evolvation is water and steel chimcar would the 2nd best because fire can beat steel and the the best is turtwig cause its evolvation is ground and ground can beat steel and fire
Piplup is stronger, cuter and more loyal than turtwig and chimchar! For example, Piplup, the penguin Pokemon can use water type attacks on chimchar, and ice type moves on turtwig!
if you choose turtwig as your starter than your opponent will have chimchar if you chose piplup then your opponent will have turtwig and if you chose chimchar than your opponent will have piplup.
Piplup, Turtwig, and chimchar
Piplup,Chimchar,Turtwig
Turtwig chimchar piplup
turtwig chimchar piplup
Turtwig Chimchar Piplup
Turtwig, Piplup, Chimchar