I went from a Pixel 6 to a Pixel 8. The biggest difference in daily use for me is the fingerprint sensor. On the 6, it was really picky/finicky. On the 8, it just works, when I have to use it. The biometric camera unlock works even better than the fingerprint sensor.
The camera also works better on the 8. Colors are better, and the app is faster when taking pictures. It always felt like there was a delay with the 6.
Bluetooth has worked well with all the devices I've used with it. Google Buds Pro, JVC earbuds, my desktop PC, and various other speakers. Android Auto works great with my car, but at this point it seems like the cars implementation has a lot to do with that.
The 8 is a little smaller than the 6. Width and depth seem the same, it's not as tall. Battery life is slightly better, I can get about a day and half from a full charge. Quick charging takes about 2 hours. Slower charging can take all night with adaptive charging enabled.
I'm not the biggest power user, so I don't know what else I can add.