Out of the box, loved the new 2 M charging cord. Long enough to reach the receptacle for once without an extension. In particular I like the iPad with home button on right in landscape mode which with the way my room is arranged, works great. I loved the fingerprint setup I can do like my iPhone. The code was also 6-digit rather than 4 enhancing security. The wifi seems far more stable and responsive than my Air with data as the Pro does 2-3 bars and the Air reverts to LTE too often. Weight is spectacularly light. Video pops. (Hardly need my reading glasses) Sound is dramatic but oddly enough, for audio music, it did better upside down. Headphones the same as any other Apple product. The backup from my Air loaded almost flawlessly from the iCloud as both are iOS9. This is important when you want to load a machine with the same stuff. The only setting that I had to reset was iMessage.
Love hidden object games and the screen plays spectacularly. Same with network streaming such as Bones from Fox, etc. your iPod section or youtube vids just rocks.
The negative is that the pencil is a ghost and will not ship til almost January. Thr logitech is available and in stores but the Apple one is another ghost at present. I got Bestbuy's Modal for mobile use—works great. Apple's keyboard is like the Surface's which is spillproof but much prefer the Logitech because of being lighted, heavier and has that nice 'key-click' I am used to from electric typewriter days...lol. The Zagg glass is also unavailable but they did have the HD version which I did not want.
I opted for wifi not only to reduce cost but do not need data as my 6+ iPhone can either create a Bluetooth hotspot or I am in network range such as at most restaurants, hotels, etc. all in all, just love it. There is a 'developer lag' going forward but this gap will probably close by Jan or so, and if Adobe's rumored 'suite' materializes and works, it will be socks off. Microsoft already has done some work but it needs fine-tuning especially conversions. This was problematic from Office 2013 on on Windows. Oddly enough, Keynote and Pages are doing very well in that department as they did also on my Macbook. Pdf is really the way to go if you want very precise renditions of final copy.
Will post other comments as I have them. This could be the machine you've been waiting for if you ride the Apple train. If all you want is an Apple product that is a Windows workalike, get a Surface or another similar product. This is a perfect consumer/light business blend.