Recently given 3 servos from Modulus (equiv to dynos on Heroku) and began wondering if I should move my operation. Heroku has been good, and has yet to cost me serious $$. Its dead simple to use and the "revert" button has saved my a$$ more than I can count.
However, Modulus specializes in node/mongo, and the servos are a nice touch.
I also have a credit from Digital Ocean, but it seems you can use that storage with Modulus? Not 100% sure