Just left my local Apple store and had my first hands-on with the iPhone 7/7+. Let me preface that I'm offering my quick impressions solely in comparison to my current iPhone 6s+.
That be said, color me wholly unimpressed. In the hand, feels exactly the same. While I think the new Black is a marked improvement over the old 'Space Grey', the Jet Black looks like plastic (reminds me of the 3G/3GS) and the display models had tons of micro-scratches along the back.
I actually did like the new Taptic home button but it's really not solving any existing performance problem. Yes, a moving home button is more likely to fail but Apple has introduced new hardware (Taptic engine) that could also fail. But while I've seen tons of complaints about the feel of the 'click', I found it to be just fine. Otherwise, I see no added benefit other than Apple testing out new tech for next years rumored buttonless phone. And according to Apple, it's a primary reason there use no longer a headphone jack.
The camera is likely the biggest area of change, especially in the Plus model---this is the only area where I'd see someone getting any value in upgrading from a 6S+.
Unless you are quite dedicated to the minutia of smartphone photography, I'd don't see the value in upgrading personally. And in the past, in regards to Apple products, my upgrade threshold is pretty low.
