The Moshi SenseCover steels a cue from the HTC One M8 Dot View case. It includes a flap that covers the screen, but there's an opening so the owner can see the Caller ID information when the phone rings. If the person wants to take the call, there's a conductive metal strip that sits where the slide to unlock/answer feature shows up on the iPhone screen when it rings.
We like the usefulness of this kind of case. It protects, looks good and keeps the camera, ports and buttons accessible. It also protects the screen and the user doesn't even need to open the cover to answer the phone. It's minimalist protection at its finest.