Edit: Haiku style:
Middleman sees mail,
welcome to privacy hell.
I would never use.
The majority of tweets in my stream since it "launched" were negative. Interestingly enough, this is impacting their App Store rating, too:
http://cl.ly/image/0Z3P412a2l1Y (Screenshot)
However, it's more the new user experience once you actually have access that's building love. Naturally, waiting doesn't build love. Maybe some excitement, but also some animosity as we saw in this case. But if you can drive the excitement as they did for some people, but most importantly capitalize on the hype when people are actually using the app for the first time...that's when you build love IMO.
I wonder if they have additional folks from the original Orchestra team pitching in right now given the fast rise of the app though. And I'm sure they can't hire fast enough right now... http://www.mailboxapp.com/jobs/
Does it make people want to use the app more or push the app out of memory?