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.
it has a few problems with lockinfo, in the lock screen because sometimes it overlaps notifications. it's a matter of changing some lockinfo settings anyway.
a part from that i would say it's very good. it lacks some important configurations but the overall experience is very well integrated.
i had no problems so far!
btw... the system to reply to sms messages with only a tap in the notification is a godsend for me.
I do use a jailbroken iPhone (for LockInfo) but am gun shy trying any other app that messes with the system.