I am one of the very lucky ones to get a new Nikon D5 on release day, (The First in England to leave a shop), on Wednesday March 23rd. It is early days, but so far, I am getting fantastic results over the Nikon D4s, previous flagship camera. Autofocus is a lot better. High ISO is real great through to ISO 102400, and higher. I have pushed the ISO to the crazy 3million through the extra ranges, but this I would not hardly use, but lower range settings could be usable. I have had trouble with the very early XQD cards, breaking up a bit, but only on the very first cards that came out using the Nikon D4. Lexar and Sony have improved the cards, and speeds are a lot faster. For me, if one wants a very fast camera, photographing sport, of other fast photography, the D5 is the one. I have not tried to take 200 pictures on full RAW, as yet.
As I cover a lot of "Non League Football" where one only has, sometimes 12 floodlights covering a pitch, the ISO is a very important factor to get quality images.
I will shortly be putting various pictures on this site to show the ISO quality, from football to an aerial flight from London Gatwick to Palma Mallorca at night. The flair on the window was the worst bit, but one can still see high ISO pictures. I personally feel that even with Canon launching their new Canon 1DX mk 2, the Nikon will be the better camera of the 2, as Canon now have a new card CF format, which means, that one will now need to buy new cards for the 1DX mk2 for one of the ports, as I understand.
All Flight pictures are untouched, and the caves are very quick Lightroom touchup. There is NO NOISE ADITIONAL REDUCTION off camera processing in any of these pictures below.