Signed up right away deployed a new server on Digital Ocean.
Really easy and powerful tool – BUT (this is a big one), why lock someone in with GitHub? Sure, GitHub is great. But what if I use BitBucket? Or even my own solution for my private projects?
This has killed many other services before for me, Pagoda Box (if I recall correctly) also forced someone to use GitHub, so did Appfog (or PHPfog rather).
I like Fortrabbits solution, where you at least can push your own code.