Well here are some day one thoughts.
When I went to restore from backup, I realized my last backup was from last August! Unfortunately, I'd already wiped my broken Air so I was SOL. Fortunately after restoring and updating, I only had to reload a few apps by hand. Remember to keep your backups in place!
True Tone is shockingly good. I always considered the iPad rather inferior to my kindle for ebooks but the improved visual clarity makes me think eye strain won't be as much of an issue. That's a killer feature for me as it means I can get rid of another old device.
The speakers are outstanding. I am a bit spoiled as my Mac has about $400 worth of audio equipment but compared to any mobile device or laptop I've ever used, the audio clarity of the iPad Pro rocks. I've never seriously used my iPad for video as I usually use my 13" Pro or my desktop Mac, which has dual 27" displays. However, the audio is good enough on this device that I might start using it for Netflix.
I am glad the weight and form factor remain constant from the Air. I absolutely loved my Air and the Pro feels like essentially the same device. Touch ID is very welcome as well. I've grown to love it on my iPhone.
I haven't run any games or intense apps yet but for basic stuff, I don't see a huge difference in performance. This is less a criticism of the Pro and more a comment about how the first gen Air is still an amazing device.
My Apple Store didn't have any Verizon sims so I can't use my cellular modem yet.
Switching to the gold was well worth it. I've kind of wanted it since the first Air but kept buying silver so all my devices would match. The gold really makes it stand out and look like a premium device though.
To be honest I would not have gotten the Pro if I hadn't broken my Air but it is certainly a quality product and the improved True Tone display seems like a huge improvement that should make Air and Air 2 owners consider an upgrade.
I won't get the pencil or keyboard for a couple months but I'm looking forward to using them. They were on my Air 3 wish list so it's great that we will get them in this form factor.
As a final note, the guys at the store were showing off the 12.9" Pro while I was there. It was my first chance to play with one. Wow! Those things are huge! I'm a big guy (6'4" 300 lbs) and they seem like to much even for me. I'll stick with my MacBook but I can see the appeal of the big iPad.