Need some guidance

I preparing to do a project which will requires ML in a neural net which will have some ''input'' being the result of a Sentiement analysis.

FYI I have followed Andrew Ng class on coursera and geoffrey Hinton's. Until now i worked alot in Matlab, but would like to do my project in Python.

What library should I use? for GPU usage? for ''simpler'' implementation ? Easy to understand? Please help me out :)