I've been using it for about two weeks now, and while I don't like to tweak my iPhone (4) too often, this is a really nice tweak. It's set to not show the annoying, interfering blue notification popups while my phone is unlocked/being used, and the "Recent notifications" list (which I have set to be pulled down from the status bar, like in Android) works really well.

I'm generally not a fan of Android's UI but I think it's one place where they've nailed it.