OK, first impressions.
Overall I like the updated look. I think it feels cleaner, more elegant.
I'm OK with the map auto-hiding the top menu bar. The menus are just a quick tap away. The time is always visible in the top right corner. I wish they'd put the outside temperature back on the main screen (they messed this up a long time ago and still haven't changed it back).
Auto zooming of the map is interesting. I think it makes sense, I just need to get used to it. Not sure if it's zooming based on speed or what type of road you're on, or a combination. One thing I noticed is that the change of zoom levels can be a bit jarring as the screen downloads new map tiles at the new zoom level. Would be nice if this were a gradual zoom rather than an abrupt change.
Thumbs up for "avoid tolls." I didn't try using navigation yet.
I didn't spend much time with Autopilot. I passed a few exit ramps and it didn't try to take any exits I didn't want it to. Auto lane change is a lot more eager than it used to be. In recent versions of 7.1 I found the auto lane change extremely reluctant to do anything, even when I could clearly see that there was plenty of room. Tonight with 8.0 I checked my mirrors and blind spot, put on the signal, and the car moved over pretty much right away.
I got one nag to put my hands on the wheel (they were on the wheel very lightly, not exerting any force). I like the pulsing white border, it gets your attention. At this first nag level it doesn't mute the music, which is good. Having my tunes get interrupted was the most annoying thing about the nag in 7.1. Maybe I just wasn't noticing the first nag before. In which case I like the new white border nag because it gets my attention sooner.
Improved regen is maybe a small difference. Might surprise a few people just a bit but not that big a deal in my opinion.
I still have several possible options for the right scroll wheel. Climate temp, climate fan speed, screen brightness, a couple of phone call things. I don't have a pano roof. Just missing the media source option.
Media player will definitely take some time to get comfortable with. I seem to have gained some random new radio station presets, and my existing ones got shuffled around. I don't like what they did with the USB media navigation. I can view a list of artists, which shows me all the artists in alpha order, but when I choose an artist it shows me ALL their songs, not organized by album. Or I can view a list of albums, which shows me all the albums in alpha order, not grouped by artist. GRR! Or I can do folder mode, which may be the best workaround for now. Fortunately I do have my USB stick organized into artist folders and then album folders within each artist folder. I know I'm OCD, but come on, the way I listen to music can't be that unusual. Hard to see how this interface got past the beta group. Do none of them listen to music albums from USB? Or does Elon just use Slacker and XM and assume everyone else does the same?
In summary, so far I'm happy with everything except the media player.