Given today is THE day, I would be surprised if you get many answers different from:
1) YES YES YES!!!
2) It's perfect in every way
3) They are beautiful!
I had the 4 and to me it is much better. Definitely lighter (yeah and thinner). Apps certainly seem to open faster and apps that used processing (like iPhoto and Hipstamatic) seem to run better. I have not tried everything that I have installed yet - just wanted to make sure that all the buttons, USB and BluTooth for my car and earphone jack were working properly.
What I really like is that the front facing camera is FINALLY decent enough to actually take a non-video picture. Again I am coming from a 4 and the resolution of that camera (the front facing one) was abysmal. Did try the panorama and the camera indoors and what I have read about an improvement in low light seems true also.
As far as maps - I have been playing with it on my iPad since the other day (when iOS 6 was released) and I do see the issues that a lot of people have seen. But I live in NYC and most of the "issues" (aside from the weird looking buildings) were related to small town type areas. Agree that Google maps were better at showing traffic. Did not use Google for turn-by-turn directions (don't even know if it had that) as I use GPS Drive for that) so I have not really played with that yet. I did try out having it display directions to some places and it was fine - just like Google with the three routes and estimated times and distance. Do agree that at times it seems the map is pointed in the wrong direction - not sure if that is an iPhone or GPS issue - but I had the same issue with the iPhone 4 with both Google maps and GPS Drive.