I managed to get to a gig tonight with the sole intention of giving my new D4s an airing. I've got to say, it's a lovely thing to use. First impressions are.. Brilliant AF, easy to migrate to (from D3s), light weight, lovely sounding shutter/mirror box and it chews through frames with aplomb.
Here are a couple of example shots at high ISO. The ISO is in the file name. The picture of the man at the mixing desk was taken in what seemed like very low light. ISO 128000, 1/30 sec F5.6 on a Nikon 14-24 F2.8