Eric,
In my first 24 hours I think that signal/LTE performance remains unchanged, which is pretty good compared to many devices. Battery life I think may be slightly improved, again, pretty good compared to many devices. Overall, the phone performs quite well with Lollipop. It seems they did a great job on the software side. It's hard to believe that a phone this old is still this good and relevant. If only all my devices could be this way. This is by far the longest I've held on to a single handset and, to this day, I don't see any major reasons to upgrade.