Design
There's really no getting around it: the iPhone 7 and 7 Plus look more or less exactly like the iPhone 6 and 6 Plus from 2014. They are now water resistant, which is nice, although they're not fully waterproof - keep them submerged in a meter of water for more than 30 minutes and things might not go your way. Samsung's Galaxy S7 and Note 7 are technically even more water resistant, but I think it's basically a push - you can get these phones casually wet now without catastrophe, and that's a big win. If you want to go snorkeling with your iPhone, you should probably get a case anyhow.

Display
he iPhone 7's new home button will elicit instant reaction from people; it's much more different than you might think. The button no longer moves at all - it's totally solid, just like newer MacBook trackpads. A linear vibration unit that Apple calls the Taptic Engine jolts when you apply pressure to the button, tricking your brain into feeling a click. It's nothing like the clumsy haptic feedback on other phones, which I've always disliked - it really does feel like a click.

Lightning Strikes
So there's no headphone jack on the iPhone 7. Apple says it needed to take out the headphone jack so it could make space for better cameras, the Taptic Engine (even though the 6S also had a Taptic Engine), and perhaps most importantly, a bigger battery. It was also easier to make a phone with one less hole in it water resistant, but Apple tells me that it wasn't a huge factor.