Not quite. In Spotify, you can sync your local files to your iPad and Android etc, but you can only access those files if all of your devices are on the same wifi network. With Google Music, you actually upload your library and you can access those songs anywhere. As a matter of fact, when I cancelled my Google Music subscription, all of my uploaded songs stayed listed in my app, I just could not no longer stream the songs that I didn't own.
You don't say.

Been looking for one of these streaming music services with just that feature. I use Spotify with my Jb i5 so i have a tweak that makes it kinda free but that streaming from your personal library anywhere option Spotify is missing.