I started reading through these but didn't have time to get through the first 3-5 pages of the oldest posts.
I woke up at 2:01 am at release... Honestly, I was surprised it went as smooth as it did. I was first able to log in around 2:20 am then couldn't get past the character creation. I then was logged out at around 2:35 am. After that, I couldn't log in until around 3:30 am at which point everything smoothed out and I have been able to get in game without acception ever since.
When I am in game, play is solid. I have yet to be disconnected during game play (save the one announced maint on the servers that was announced before they went down).
Given the volume, I was quite satisfied with how the release went and I absolutely love the game. My step-son has been playing with friend ever since release and has had nothing but good things to say about it. My five year old has run three builds (Monk, Wizard and Demon Hunter) and has also had no complaints ;P).
Just thought I would recap my experience on release day.