My 32gb arrived yesterday late morning, used it on and off most of yesterday afternoon & evening.
Impressions:
In the box: Nexus 10, Quick Start manual, USB to micro-USB cable, USB adaptor & wallplug
Hardware:
Construction seems generally solid, I like the "grippy" rear on the device - you get have it on your knees without fear of it slipping off. My only gripe is how quickly the screen gets finger-print splattered, but that's a general tablet gripe rather than a Nexus 10 gripe.
Set-Up:
I had ticked the "link to my account" box upon ordering, so it greeted me by name when it booted up. Entering my Google password kicked off the quick & easy set-up process as any applicable apps (not all of them were) are downloaded onto the Nexus 10. Then came a OTA update to Jellybean, and a re-boot. Boot process is very fast - from switch on to login screen seems about 10 seconds.
Display:
As others have said. it is sharp. Very sharp. Zoomed text on web pages looks great. Games look great. Apps optimised for the tablet look great. No complaints about performance. I installed various widgets for email, twitter, FB etc. all without any issues.
User Accounts:
An excellent feature, and was very easy to set-up if you have google accounts for all users. Great for sharing the tablet around the family. My only concern is that now when I purchase an app on my account and someone else in the family want to use it, I will have to purchase it again for them - which is a bit of a gyp.
Battery:
Device came with about 70% battery. I plugged it in to charge whilst I was doing the set-up etc. During this period the device did not seem to gain any charge, but stayed about the same. When left alone on charge (not switched off), it seems to take a long time to charge up - probably managed about 10% in an hour. Left overnight it charged from 50% to full, no problem, but I'm going to see if a 10% or less battery will charge fully overnight tonight. Will not be very happy if it doesn't!