Hello! I upgraded from a 6+ to a 7+, and I'm really happy I did it. This phone is much faster for me; I can put the two side by side, and this one renders images and downloads emails at least twice as fast as my "old" phone. It opens apps right away, too. I also find the screen to be significantly better--the colors are richer and deeper, which I love, and the slightly warmer white point makes reading eBooks easier on my eyes. Speaker sound is great, not only for music, but also for using speakerphone on conference calls for work. I take a lot of animal pictures and portraits, so of course I'm enjoying the camera improvements. My favorite changes, though, are the new home button and the 3D touch features within iOS 10. They allow for small timesavers that really add up, especially when reading/sorting email and responding to messages. Battery life is good; I usually have to charge only every other day.
For anybody wanting to know about battery life on the regular 7: I had one of those, too, in the beginning. I had badly wanted to downsize to the smaller model, for one-handed use and more portability, but I couldn't get used to it and had to exchange. Anyway, I had a 7 for almost two full weeks, and I can say the battery life on it was fantastic, too. I still could get through a whole day and have plenty left for standby at night, and wait to charge at work the next morning. I did not notice that the screen resolution was any less beautiful on the smaller phone, and, like the 7+, it handled everything faster than my 6+.
As other people have said, I wouldn't call the upgrade from 6 to 7 a necessary one, or a wildly exciting one (exterior design change-wise), but it's very nice.
