Trezeguet, Van Nilstelroy, Shevchenko, Romario, Crespo, Drogba, Batistuta, Zola, Ronaldo, Luca Toni, Klose, Vieri, Inzaghi, Lewandowski, Aguero, David Villa, Suarez, Klinsmann, Stoichkov are examples of great finishers.
IMO Ibrahimovic is not in that group. He is very talented technical player with an impressive goalscoring stats, but often chokes to finish simple tap ins in big games. The same I would say for Cristiano Ronaldo BTW. Both are incredible players though.