I took the time to explore the new toy as I already had an iPhone 6. Basically, they look the same with a few differences...
As you can see, the camera size is a bit larger, making, as always, great pictures. There is also the button that does not move at all, probably to support the 3D Touch features.
As for the headphone jack, it's gone. The new iPhone 7 does come with a new headphones with a lightning connector. Don't worry, it also comes with an adapter so you can still use your "old and obsolete" headphones... ;)
Overall, this is a great device, with some new features that are not essentials but does provide a great quality.
After a few days, I feel at home. I gained the new features of the iPhone 6S and got a few extras with the iPhone 7. I would not say that this is a mandatory update for anyone already having an iPhone 6 or an iPhone 6S. So why did I upgraded?
My son wanted to move on from his now obsolete iPod 5 and I like new stuff. So we played the iPhone merry-go-round at home. The iPod 5 went to his younger brother, he got an an iPhone 6 and I got the iPhone 7...