I have achievements working ok, but am not getting a notification when it's achieved. I can go to game center and see that the achievement has been awarded.
Noticed this from the Apple page.
Quote: ""
By default, when an achievement is completed, Game Kit displays a notification banner to the player. If your game wants to display its own achievement user interface, you can prevent the banner from being displayed by setting the showsCompletionBanner property of the achievement object to NO before reporting the player’s progress.""