I've seen the rather annoying and desperate EE adverts (UK) with Kevin Bacon hamming it up about the camera.
Is that it? OK there might be some other bits and pieces, but if that's the main selling point I'm not seeing the attraction. If I wanted a brilliant camera I'd buy a brilliant camera.
Likewise, I'm a bit of an "audiophile" and the DAC in the S8 is what you'd expect. It's crap. (For comparison it's fractionally better than the one in my old iPhone and it isn't tonally biased to make everything sound like syrupy, crystallised glass). In hi-fi terms. In terms of what I'd expect from a phone, it's.. alright.
Some crude ten quid chip, maybe. It's alright for plugging into the car system. It is not a piece of hi-fi equipment. But it isn't meant to be. If you want top quality sound buy an external dedicated DAC. Or a really good turntable, tonearm and cartridge and listen to stuff from before when the "loudness wars" came along and wrecked sound quality. No device can "fix" that.
The S8 performs quickly enough, indeed at times it puts my Windows 10 PC to shame.
I can't see any "killer app" or reason to upgrade. But then I regard my phone as a "peripheral" device. it means I can look stuff up on the internet (though the experience isn't the same as with a dual-monitor Windows PC). I can read emails. I can type out quick short replies to them; if I want to type something lengthy I'm not going to do it on a device with no physical keyboard, I'll wait 'til I get home. And I can read Tweets.
That's probably about all I use the phone for. So in this respect, a better camera and a faster processor are worthless to me. That said, were this my primary means of accessing the internet, my views would probably be different.