Google has recently put together a great article about the differences between designing for iOS and Android, linked below.
Any designer should read this, it covers everything from navigation paradigms to interactions and motion.
http://www.google.com/design/articles/design-from-ios-to-android/
A week into wearing an Apple Watch, I’m a huge fan of it. Being fairly active I love the Heart Rate sensor and activity tracking. Also, being fairly tied to my phone and computer it’s been great to get subtle taps when a new email or notification comes in. When at home, my iPhone 6 Plus sits on the coffee table and I only go to it when I want to respond to a text without looking like I’m talking to myself.
Where it fails:
Force touch isn’t intuitive yet, some apps use is, some do not with no indication of if it will do anything.
Apps seem to install automagically when an update is pushed despite that setting turned off. I was very selective when setting up my watch and only installed a handful of apps. Recently some new apps have been showing up on my watch, they promptly get deleted, but it’s still annoying.
Apple Watch iPhone app is slow and often I’m stuck looking at a black screen for awhile.
Needless to say the apps kind of suck and run really slow.