I'm back on Google App Engine Java 8 runtime with a Clojure(Script) stack. I haven't found anything comparable yet that offers this amount of flexibility, scalability and generous free tier to get started.
Google seems to take Steve Yegge's Platform Rant [0] as a blueprint to try to beat Amazon at the Cloud game and creates an API for anything you can think of.
As usual, the documentation and their support is terrible, but who needs support or documentation when you have a REPL?
It's been a real pleasure to work with and I'm currently in the process of open sourcing some tooling libraries to smooth out the rough edges (Caveat: These are not stable yet, so use at your own risk).
Currently working on a CLJC REPL over HTTP integrated with Emacs, but the following are available already -
Example ring project:
https://github.com/alpeware/jaq-example
Leinigen plugin:
https://github.com/alpeware/lein-jaq
Clojure bindings for App Engine services: