I agree that Carrara's renderer is faster than PP 2012's. I don't know whether it's faster than PP 2014 though. I don't have any comparison data.

Shade's renderer is awesome, better than Octane, if you ask me. It's also very fast. The great thing about Shade is that you can get beautiful renders out of it very quickly, with mimnimal tweaking of sahders.

The only thing I can think of to speed-up your render time is to not use skylight, but simulate it with several distant lights. Depending on how you place your distant lights, you could get anything from a dull to a very good render, so you will have to experiment.

Also don't use full indirect light, but AO only, as you seem to be doing anyway.

You could push the other options (like uncheck the interpolation, increase the photon count and the photon map accuracy). These will improve the render quality, without the speed penalty of a skylight.