It's trivial to upgrade from 2.7 to 3, you can pick based on the availability of the libraries you plan to use. If all you need has been ported to 3 just go wit

It's trivial to upgrade from 2.7 to 3, you can pick based on the availability of the libraries you plan to use. If all you need has been ported to 3 just go with it, otherwise you can use 2.7 and make your code future-proof by importing some things from __future__ (the print function, unicode literals, etc.).