Well, once there is PyQt for Harmattan, I can switch back. But right now I am not willing to maintain 2 branches just because of the backend.
If you can show me that pyside installs a bigger amount in the rootfs, then we can think about it, but as long it is outside rootfs I dont see a reason not to use it.

Beside of that, pyside actually has the better licence compared to pyqt as it is available under the LGPL.

And another beside:
Just dont use sleepanalyser from the devel tree. The testing tree one still uses pyQt