I have been running the 10.10 beta for OSX Yosemite on my MBP for a while with no significant issues and yesterday installed iOS 8 on both my iPad3 and iPhone5. The iPhone completed without issue but the iPad was bricked with an apparently forever phase of “verifying update software”. I was forced to restore it from backup and then it updated to 8 without any problem. It did need to update 138 apps (I have too many apps on it I think but I use it for quite a bit) which took quite a while (more than an hour) but eventually finished.
iOS8 on the iPhone has appeared mostly the same to me in appearance and I notice a few new apps (Health, Tips). So far Health is running without input from any other apps which I think is one of its primary benefits. I have a FitBit One and scale and it would be very convenient to have the weight and step data collected from them be automatically imported as health data.
I have noticed that my iPad3 seems to flicker a little more in Safari as if it is doing something else at times. I am not sure exactly when I notice it nor what it might be doing unless it has to do with sync’ing stuff across all of my devices.
More to come on this subject.