Tested it with my Google Apps For Business account, doesn't work. Get this error "your organization isn't set up for inbox yet" and their FAQ shows it only works for personal accounts... no way to add it yet via Admin Console, either.
Oh well, enabled it on my secondary Gmail account, to play around with it. I don't have an Android device on me currently so I used Blue Stacks to download the app, and now I'm getting the web app/extension for Chrome.
EDIT: Pretty neat. I like the clean, Material design look. Setting up some bundles now.