Here is my experience:
It is 11:00PST, I'm doing an OTA on an iPhone 4. I started downloading at ~10:15PST and it just started installing, I have the verifying update dialog. I am so excited. Here is the first reboot... Now the Apple logo with status bar, it moving fairly quickly...Well maybe not that quickly it seems to be stopped a the beginning of the bar...Just saw it move a hair, the progress is about the size of two charger cords, not very far...come on, I am waiting...10 minutes later and it's ALMOST half way...I can hardly breathe I'm so anxious. 11:26 and still waiting....it just over half way. getting closer, maybe 1/4 left to go...11:37 and I can only see a sliver left to go. Now I just see the Apple logo....And the progress bar came back, this time it is moving faster than the first time. Only took to 11:44 and now back to the Apple logo. Screen went blank and then the logo came back, it's 11:47. How many times is it going to do that? Maybe I shouldn't of, but I just forced a reboot, it's 11:54. 11:57 and just got the iOS 6 screen. 11:59 and I am ready to use my phone!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!