In installed Nougat OTA via Spark a few weeks ago. I have an S7. Some things I have noticed so far.
Like: The call-hold button has moved. On the previous version I kept touching it with my ear and putting people on hold.
Like: There is now an SM widget that appear in the pontification area allowing quick read and reply of an incoing SMS without changing screens.
Dislike: Less ability to control what apps do in the background via Device Maintenance. I can't find a way to designate an app "always manage power" or disable.
Dislike: In Application Manager I can't find way to disable a downloaded app. You can only un-install it. I used this option for apps I find useful occasionally, that run in the background.
Probably need to download a third party battery manager now ...