I tried an early version on a Samsung Galaxy S9 Plus, paired to a Fossil Q Explorist HR watch.
In the watch face, Wear OS now has swipe gestures for each direction that bring up new things. Swipe down, and a larger control panel of shortcuts (and music player access) are helpful.
Notifications are more compressed. Swipe up, and it's easier to scroll through them. There's less chance of missing something.
Google Fit is redesigned, and accessed with a swipe-left. The new goal rings are based on movement and heart rate (daily activity and more active minutes).
The preset activity goals feel too forgiving for me, but they're adjustable. It's still better than Google Fit used to be.
Swipe right, and Google Assistant is there. Voice requests can be made with a tap, and there are some suggested results that automatically pop up.
If you have patience, Google Assistant on-wrist is by far the best assistant versus Siri or Samsung's Bixby.
Google Assistant search results are a little hard to scroll through sometimes, but Assistant also brings up suggested search steps afterward in little clickable boxes.
As always, there are plenty of random and sometimes good watch faces in Wear OS. That's still the same.
Watch faces and complications on the watch faces remain the same since last year, but you can't swipe left or right to swap faces anymore. Instead, pressing and holding on a face is the only way to select.
The same goes for app access: Press the side button, and a scrollable list of apps is on tap.
Wear OS works on Android phones, and also iPhones. But iPhone users are far better off using an Apple Watch.
The Fossil Q Explorist is a solid example of current-generation Wear OS-compatible watches: It has NFC payments and heart rate, which last year's Android Wear watches often lacked.
If you're curious, here's a look at just the watch. Full review to come. But if you have an Android Wear/Wear OS watch currently, the new Wear OS update is a big help for easier at-a-glance access.
Take a look at a few more pictures of the Google Wear OS update.