Waitress vs Gunicorn etc

[Robert Grant]

Having read the nicely-written Don't use Gunicorn to host your Django sites on Heroku, I'm in the standard non-expert position of thinking that it seems well reasoned, but because I don't know what I don't know, I can't tell how balanced the reasoning is.

What I've gathered is that for Heroku (and possibly generally), Nginx+Gunicorn is better than Waitress, which is better than just Gunicorn.

Is that right?

Bonus question: is Waitress a good candidate for a drop-in runserver replacement that can actually run in low-volume production? :)