[paxys]

Heroku is terrible value for money. You can very easily use one of the dozens of free & open source deployment managers or CLIs for EC2 and get the same ease of use at 1/10-1/20 of the cost. It's good for hosting a hobby project for free or $5/mo and forgetting about it, but it doesn't make any sense for a startup.

[bredren]

Or side project. There is a learning curve to heroku of its own, and you could be spending that time just learning how to deploy docker containers.