I've been on the iOS26 beta since it first came out. Its been polished a lot since then and I think they've put out a good product finally. Aside from just the new liquid glass design the functional differences are nice.

I switched my icons to dark mode. Its just a nicer look and possibly less distracting with less color there. There's a clear mode too but I think its too washed-out looking.
The widgets I haven't played with much, but I see the calendar and weather being somewhat useful. FWIW I use the app MyRadar if I want to see a weather radar display while driving. I don't have compatible useful smart home apps but hopefully MyQ for the garage door will appear eventually.
Display zoom makes better use of the display. The icons end up being smaller but more map is displayed and more items on a scrolling list are displayed, therefore there's less scrolling required.
I have a few teams saved in Apple Sports so the live activity score updates is awesome. My kids no longer have to ask me if the score has changed!
And finally, the screenshots option is a welcome change. Screenshotting the CarPlay display is almost never the goal.

 

It's too bad that iOS26 only displays 2 rows of icons on the 11.6" vertical screen. The smart zoom feature doesn't do anything to change this behavior. I'm not sure if this is an Apple issue or a Subaru issue.