I don't have a lot of experience, but I recently ported an RNN model from lasagne/theano to keras/tensorflow, and the latter combination was about 4x slower. No

I don't have a lot of experience, but I recently ported an RNN model from lasagne/theano to keras/tensorflow, and the latter combination was about 4x slower. Not sure whether it's keras or tensorflow causing the slowdown. The API is nice though. I also tried to flip the keras switch to run on top of theano instead but it had issues that I didn't have time to fix, so I just stuck with the original lasagne/theano stack.