Rock solid. We've have had 2 fire 7's in our house for 1.5 years, in the hands of a now 8 and 6 year old and no issues. Things are covered in gunk (like how they manage the touch screen is beyond me), and they keep going.
I don't use unlimited, I've side loaded play store, set age range, enabled full parental controls on play store and on the tablet themselves... They have full control, but web is blocked etc. Play store is great, tells them they need to uninstall things to install the next game. They don't need my interaction to install X or Y now.
They did manage to download an app that let them have full access to unfiltered youtube, but we caught that pretty quick. YouTube kids is great as well.
I don't use unlimited, I've side loaded play store, set age range, enabled full parental controls on play store and on the tablet themselves... They have full control, but web is blocked etc. Play store is great, tells them they need to uninstall things to install the next game. They don't need my interaction to install X or Y now.
They did manage to download an app that let them have full access to unfiltered youtube, but we caught that pretty quick. YouTube kids is great as well.