Some really good, real-world observations in this thread. Having used all of these phones (and the 6), I'll add my own:
6 is indeed noticeably slower than 7, 8, and X(s), but it's also noticeably thinner and lighter--things that mean a lot to people who don't like being weighted down with small bricks in their pockets.
Phone call quality (how people hear you): noticeably superior on the 6 to any succeeding phone. Apple must have changed something with the phone circuitry in the phones after the 6, and the result is thousands of
valid reports of degraded phone call quality, both on the 7 and 8. I haven't tested the XS in this regard, but my hopes are not high. Apple seems to have forgotten that there's the word "phone" in iPhone.
7 is both lighter and thinner than the 8. That means a lot to some people.
8's speakers are noticeably better than 7 and a lot better than 6. I can and do listen to music sometimes just through the speakers of the 8. Good hotel phone.
6, 7, 8: they're all too slippery. The one usability improvement on the XS that I've noticed is that it's less slippery in the hand.
Fatter, heavier: Apple is definitely an American company in this regard. With each generation, it keeps making phones fatter and heavier. What's up with that? The company must think we all carry little red wagons behind us that we can put these things in.
Apple leather cases: if you want to like these (as I do), note that after the 6S series, the leather cases started getting slippery. There are exceptions, but they seem to be isolated rather than the rule. It's weird: the company makes slippery phones, and part of why you put a case on it is to make it less slippery. You'd think the brain trust at Apple would understand this, but no: they continue to release leather cases that are almost as slippery as the phones themselves.
Cameras: optical image stabilization should be on both lenses of the dual-lens cameras, and it is only on the X(s). That's a shame. But I suspect that if you're serious about photography, you won't use a camera phone anyway. Even the best aren't that great. That said, if you're a photo nut, the camera on the X(s) is the only feature that's really tempting on the newest phones.
