Some more notes on the Surface Dial:
1. It's super-satisfying to turn, and uses rumble feedback to really give you a visceral "click" when you turn it or push it in.
2. I didn't end up using it much in my day-to-day use. It's neat, but the novelty of using it to change the volume of my music or scroll up and down in Google Chrome wears off really quickly.
3. In theory, the Surface Dial adheres to the Surface Studio's screen when it's in the tablet mode, using a tacky surface on the Dial's underside. But if that bottom of the Surface Dial gets dusty or covered in crumbs, it won't stick to the screen as well. Just, um, trust me on this one.
4. It still works when it's not attached to the screen. Just, you know, see point #2.