I know you are saying, "let's say" they are mutually exclusive, but I would highlight that they are not just _not mutually exclusive_, there is actually an open

I know you are saying, "let's say" they are mutually exclusive, but I would highlight that they are not just _not mutually exclusive_, there is actually an open-source PaaS that is built on top of Docker (CoreOS, Fleet) to be as close as possible to Heroku-compatible. http://deis.io http://deis.io And, it's not really a given that it's cheaper to use Docker. Scaling costs more, however you do it. If your project is short-lived, then the up-front hardware costs of building a cluster out of bare metal might just eclipse the aggregate amount you would spend on Heroku in that span. Even buying the machines an hour at a time from AWS, building a cluster out of them and configuring the load balancing through ELB, without counting the time you'd spend on all that, might not really save you any money unless you are actually using a whole lot of dynos. For the sake of argument, putting all of that aside, do you want a platform that just works, and you just pay the bill, or do you want to know how it works and have some direct control over actual downtime, upgrades, etc? It's not really fair comparing Heroku to Docker. One is a platform/service provider, the other is a piece of software (not even a full platform stack.)