Android Wear:
- Cant customize clock faces or anything really on the device itself.
- Has no Home screen.
- Has almost no standalone apps.
- Has only card interfaces so can't see more then one thing.
- Mostly notifies you of notifications and opens it on your phone only.
Apple Watch:
- Has much more futuristic watch faces. Im loving the Astronomy clock!
- Actually has a home screen with already a load of apps, could have hundreds of apps soon.
- Nice fluid UI when scrolling around and zooming in with its digital crown.
- Has a nice standalone message, phone, and mail app that you can reply, delete, without touching your phone.
- Has new ways of communicating where you can draw, tap, send heartbeat, etc.
- Has a walkie talkie feature.
- Better more accurate fitness tracker.
- Has a sensitive touch screen that senses pressure touches. Hard press for second click, soft press for one click.
- And the potential to grow to the masses enabling developer interest that takes advantage of the watch a lot more.