Such a HUGE improvement. First and foremost, a big problem for people was the RAM management. It would only keep open a few apps (without a redraw) before closing them. Now, it seems to keep open more apps, but when it doesn't, it redraws them nearly instantly. That really speeds up this phone. Also, every little animation and transition is smoother and faster.
Turning on my flashlight is instant (as opposed to a near 1 second delay). Using overview to select an open app is much quicker. The fingerprint sensor unlocks the phone much quicker. The lock screen now allows us to unlock via fingerprint or pin, instead of either/or (now works like my wife's iPhone 6). The fingerprint sensor is much more accurate and sensitive, meaning no mis-reads (so far) and a less than perfect placement of finger to use. A few new items in settings, plus a little rearrangement. Plus, to unlock via pin, it now takes another step: now you have to swipe to get to the pin pad, then input your pin. Camera seems to be the same, save for a small red record dot, instead of a video camera icon, on the camera's home screen when you want to record. These are all small changes, and you might be thinking "big deal, I'll just stick with lollipop". But you shouldn't. All these little changes lead to a HUGE upgrade. It's now the super-smooth super-fast flagship that we all deserve, that will still be relevant in a year (10 years in tech-time). P. S. I have NEVER been one to upgrade firmware immediately, especially being a verizon customer, but lollipop was never implemented well on the note 5. Marshmallow rules all. Be bold. Do it.