Purely looking at numbers Karimi has the edge. He lasted two years while Daei and Hashemian departed after one. Karimi has 42 games for them and 4 goals and 4 assists, Daei has 32 games and 6 goals, and Hashemian has 15 games and 1 goal.
Numbers aside I think Karimi fit in the best, mainly because of his position. If you are a forward there are only 1 or 2 spots on the field for the player while a midfielder has more opportunities to be somewhere on the field depending on the formation. So in that sense I think Karimi had the best career at Bayern amongst the 3 of them. Given his low goal to game ratio is, Daei's time there was average to bad. I consider Hashemian a flop there.

Keep in mind I am not talking about their overall level but just how their career was during their time at Bayern.

What are your thoughts?