I've been using the beta for a while now.<p>It's still (obviously) a beta, so you will get frustrated every so often if you're using it daily. I love mailbox and I'm still using the beta, but I usually yell at it (mentally or out loud) once a day, so just beware!
I would love to use this, I really would. The UI is great.<p>But I can't get over the fact that all of my emails would go through a third-party service. It's just too much to ask these days.