I have upgrade both my iPhone 5 and iPad 3 and frankly I am delighted with the changes. The first thing I did was to down load the new manuals in iBooks for the iPhone and iPad so that I could at least review the features. Any one whom has glasses I recommending going with bold text in addition increase the font size for reading documents. The first option will make the device restart so be aware of that. Again once you install 7 do a reset on off button and home key. I went with a darker back ground which suited my needs. Yes out of 180 apps I have only s couple that are misbehaving however they will be fixed once the apps are upgraded
I strongly recommend downloading the manuals as even for experience uses they are most helpfull. This is essential for any user whom have issues with battery life or look and feel. I have no issues with battery life and performance is if any thing it appears faster. That's my 2 cents worth.