That's great if you have one screen of apps, but really pathetic when you have to swipe through 5-10 screens so you can see your AP news app has an update. Even worse when you have to then hunt for the update once you get in the app (AP again, or Facebook).
Not to mention, you can't ignore a notification so you can look at it later... It's either view or dismiss.
They're only one rung above notepad.exe's "Search reached end of document | Ok" dialog, but only because for most of them hitting Ok takes you to the source of the notification.
They're a disaster compared to Apple's desktop HCI guidelines that insist on verbed dialogs and disdain "Cancel | Ok"