iOS 8 was released around the typical time of 10 AM Pacific Time (1 PM EST) and I installed it on both my iPad 3 and iPhone 5s shortly afterward. I set aside about an hour to do the upgrade and it was done in about that time. Most of the time was just waiting. It didn’t take long for the download portion, most of the time was spent preparing and doing the installation. My iPad 3 took longer thanks to the slower processing.
I skipped the iCloud upgrade on both devices.
The upgrade was uneventful on my iPhone. I did have a problem with the Audible app. It would crash right after starting but this occurred prior to the upgrade and began when I upgraded the Audible app. I hoped the iOS 8 upgrade would fix the issue but it wasn’t to be. I ended up uninstalling and reinstalling the app which did resolve the issue.
My iPad upgrade was a bit more eventful. It got caught in a loop prompting me to “authorize” my app store account when I tried to download app updates after the iOS upgrade. I eventually cancelled it and all was well. I was also prompted twice for my iCloud credentials (three times if I count the prompt during the upgrade) but these did stop. I didn’t have either of these problems on my iPhone.
Apple apparently pulled Healthkit integration at the last minute until a bug could be fixed. I’ve also been having problems finding some iOS 8 apps in the app store via search. It may be that they haven’t been pushed out yet. Other than that it’s been uneventful although I haven’t used the updated software very much.