[robertfw]

I started with Flask, moved to Django, and now at work am back on Flask. It all depends on what you are building; if you are going to need some ORM, standard auth, etc, Django is a no brainer. However if you are going to be building out much of your own idiosyncratic architecture, Flask gets out of your way and avoids including lots of things you don't need.

For performance, we are building some parts of our system with Clojure. It feels extremely well suited, albeit with some initial learning curve.