For anything but simple apps like this PaaS fall apart, first the pricing scheme is no inline with even a basic VPS. As you need to add features, if they don't support them your fairly screwed. App Engine took a year to add cron jobs. They still have a proprietary engine that I have to custom code for, and if you ever want to switch vendors you basically have to rewrite everything. TLDR : If you can rewrite all the code for your service in a few weekends then its fine to be on a PaaS