I was happy with my 6+, have only had my 7+ for a couple of days. So far I am content, but not thrilled. It actually crossed my mind to return the new phone, but I won't do that. Camera is definitely better. I am fine with the new home button after being apprehensive about it. I can't really tell a difference in the improved screen. I think I can tell a difference in the speakers, but that's not a big deal. I was satisfied with the speed and battery life of the old phone, and based on limited use I am still satisfied with the new one. Those who do heavy gaming or number crunching on their phones will presumably be more impressed by the new processors. If I have a water incident I'm sure I'll be grateful for the sealing improvements.
I'm a serious amateur photographer, so the Biggest improvement for my uses is the significantly improved camera, but it still isn't good enough to replace the high end pocket camera I use when I know in advance I'm going to want a camera.
I want to get into the Apple Upgrade Program, and I got a good price selling my older phone. Those pushed me into keeping the new phone, but I definitely consider this an optional luxury upgrade. I'm not unhappy, and the phone is as advertised. If you want it, and the cost of the upgrade isn't onerous for you, you'll probably be satisfied, but I doubt you're making a mistake if you skip this time around.