I have Inbox, but never used it, main issue is that it doesn't work on my primary e-mail address (@myce) as this is hosted on Google Apps. So it works only on Gmail addresses I don't really use.
I wonder what you think about it John, I've send you an invite to the e-mail address associated with this account. Once you have it, you can send invites to any other accounts you have too and of course to others. If other people want an invite let me know here!