I'll trot out my standard question whenever Realm hits HN: when are you going to have a Browser Javascript client? Our clients want iOS, Android & web apps, so we can't use Realm until we can hit all three.
We don't need the full disconnected functionality that your mobile databases have, I believe that a thin layer on top of your object storage would be sufficient -- we could assume full connectivity when the app loads and when it exits (by hooking onbeforeunload).
Realm looks awesome, I'd love to dive into it more.