Got a chance to pickup a D5 earlier today.
In case there is interest, I am happy to share my first impressions as they develop while using the camera. Please don't expect a formal review or test. There are more qualified people out there for this. Plus, I don't have (or don't want to spent) the time such a review would need to be at the necessary quality level others would find useful. I'd rather prefer a kind of logbook approach, noting down my personal impressions and experiences while using the D5.
(As a matter of transparency: My own D5 will arrive (most likely) next week, like all others who have ordered a camera. Being curious, I asked if I can get a loaner for the weekend. Lucky me, the surprising answer was "Yes" 
. So I will start this log with this production D5 and continue with my own D5 later next week. No conditions, just my opinions and experiences.) As said, please don't expect a formal review here. D5 NEF's and JPEG's will be shared as well.
Logbook entry #1:
1) On first touch: Looks like, smells like and handles like the familiar single digit Nikon bodies
2) First thing different I experienced vs. all predecessors: The mode button was moved to the other side of the viewfinder. The ISO button is now there where the mode button was. Makes sense, as the ISO setting changes (in my case) much more often than the exposure mode. It is just a matter of familiarity (and unlearning 15 years of behavior). Index finger on the button and with the thumb changing the ISO speed, or index finger on the button and with the middle finger changing ISO -> ISO Auto, etc ...
3) Putting a lens with a cap on the D5, and if ISO is on auto the camera try to compensate for the darkness. Iso goes up to 400k or 800k. Was a bit irritating at first look, as these values aren't so often seen.
4) Took only a few images on the way home. Looks like the exposure meter doesn't need the -0.7EV I usually set my cameras to (to avoid/reduce blown highlights). Exposure metering seems to be very precise on first images. Nice, need to look into this more with a direct comparison with the D4.
5) Single focus field is not as fast as "auto group". Autogroup with a fast lens is very fast. AF auto group seems to be needed with the ISO performance of the sensor to capture focus in dark settings. Otherwise ISO performance of the sensor is "higher" than the AF system (on single AF field).
6) Sound is similar to D3s/D4. Wouldn't call it differently, if not checked sidebyside.
7) NX-D version 1.3 can't open D5 NEF files - update is needed.
8.) Windows 8, can't display "official" ISO values beyond 65535 (seems to be a 16bit unsigned integer). (Hi1 - Hi(x) values of all cameras don't show up in Explorer). Will probably be fixed in an upcoming update with support for the D5 metadata.
9) The camera has 2x CF slots
10) After the first 100 shots, 4 terms pop up: 1) Familiarity, 2) precise exposure, 3) fast AF, 4) dependability.
cheers,
Andy
