The max monthly spend is awesome, I'l probably try it out just because of that :)
Its a bit unclear to me though how exactly the heroku deploy works? Is it basically a replacement for the web dynos that heroku provides, but then still connecting to existing postgres instances for example?
What are the limits for the redis store? I'm using it on heroku but constantly running into max connection issues, if you can improve that experience it is also a great win.