I think I'm seeing my battery lasting longer, and my WiFi finding signal faster. Also, I am seeing 4G+ more often than i used to (just not in my office).
Face Unlock works well but obviously not as quick as fingerprint.
I'm not a huge fan of the Multi-tasking screen now, harder to close individual apps, though looks better and the Notification Bar is nicer to see. Since I use 3rd party launcher, no change in how the rest looks but the overall experience seems a bit faster, opening and switching apps etc.
Some youtude video mention you can unlock the phone by taking your own picture and print it black/white to unlock phone (color photo cannot). Anyone try?