Just as a counter, I'm a (current) Pebble user, and I bought an Apple Watch and returned it. I don't need fitness tracking, the Apple Watch's screen was a little too hard to see outside, and the UI was too cluttered for the type of super-quick tasks I want to do on a watch. (I also really really disliked the lack of an always-on screen, which didn't exist until a few months later.)

I like my Pebble because it's a watch first and foremost—I've worn a watch since I was around ten years old—but it just so happens to also show me notifications, and glance at things like the weather and my calendar. And I can do all of that super quickly.