Gunicorn isn’t just “trendy” it actually works really well, in some cases (like mine) works much better than uWSGI. (also it seems that uwsgi is now becoming trendy, so am I just a hipster for switching to the uncool option :P)
I have always been a big fan of the uWSGI project. It has always been my number one choice of deployment of python web apps, running behind nginx as a reverse proxy. I have always checked to see if there is anything better out there and have always decided to stick to uWSGI. Data like [Nicholas 2010] [Kgriffs 2012] [DCramer 2013] made it easy for me to stick to my uWSGI choice and make my argument for uWSGI over the more “trendy” gunicorn [DCramer 2013].