OK, got mine and here are some impressions - coming off a Lumia 920 and wife has Samsung Galaxy S6 for comparison:
1. Wow, this thing is light..and slick.
2. Screen is pretty amazing
3. Had a bit of a setup issue in that I did a restore from the 920 and it wasn't pretty. Reset and started from scratch. ATT has bloatware on it and I removed it. However, I still have two apps that will not update: Advanced Info and Lumia Help+tips. Error codes thrown which can't find anything related.
4. Phone gets warm
5. Hello Windows sign in is pretty cool and fast
6. Build quality seems good but cheap. I expect as back covers by mozo are added, it will be premium looking and feeling anyway.
7. Haven't used the camera yet
8. Since I haven't played with Win 10 mobile and the apps, there are some nice features I haven't seen before and nice apps like Pandora.
Overall, I am very pleased. I think the glance and Hello, Windows features are really awesome. Now to continue playing...