After just 18 hours and 2 different iPhone 7's I have just returned the 7 and gone back to the 6S.
As of right now, the 7 is not a superior phone to the 6S in my opinion, for the following reasons:
-Yellow screens. This is a problem every year when they change the display. The good screens will come back in a few months. I think this has something to do with the manufacturing process of IPS displays. A residue is deposited for the first few million. In a month or so, the clear blue screens will return. This isn't glue, intentional, more correct, or any other BS reason we hear every year. Its a defect of the manufacturing process. 2 iPhone 7's I got both had vastly inferior screens to my 6S, even after color profile/tint correction. Contrast, clarity, and brightness all worse than the 6S.
-No noticeable speed increases. I put the phones next to each other and tried my hardest to make the 7 run faster. It didn't. In some cases web pages loaded faster on the 6S. Plus the intentional delay after clicking the home button that was introduced in the 7 makes it feel slower and laggier.
-Marginal at best camera improvements
-Weird home button that doesn't work unless pressed with bare skin (no more gloves).
-Legitimate concerns about the lack of sapphire (lower quality materials)
And for all this what do you get in return?
-No headphone jack.
No thanks, Apple