Heroku.
It just isn't good. I tried it way back and most of the time it turned into a struggle that wasted hours.
I recently went back to it, thinking that it should be good now; it isn't.
My typical environment for a site is supervisor + nginx. Nothing crazy, super simple.
For whatever reason, the heroku instance refused to take in my config (set with `heroku config` and it was showing up in the Heroku console... but my service was like "nope, not there". The keys existed on process.env but were empty).
After about an hour I said "whatever" and stood it up on nginx + supervisor in 15 minutes.