I launched the MVP (and have so far kept it) on Heroku for two reasons

• Easy to get the service up and keep it up
• Great REPL support

Having easy access to a production rails console makes it really easy to do adhoc customer support work without having to do the upfront work of building an admin UI. I'm still primarily relying on prewritten code for safety and repeatability's sake, but use the CLI as my UI into those functions.