What functionalities are limited on iOS? I'm curious, because I'm considering Pebble watch as I'm disappointed with Garmin.

Migicovsky wrote an article on it:

https://ericmigi.com/blog/apple-restricts-pebble-from-being-...

That said, I'm happy with my Pebble on iPhone (though I'd be happier if it had fuller access).

Now with Pebble you only receive iOS notifications.

Soon in Europe you can reply to notifications via voice.