Took me a while to decide. Both have respectable specs, but ultimately i felt i had to give the VAIO Z Flip a chance. It has a very nice build, and it's fairly powerful compared to other tablet PCs, and the design is very compact. The display folds nicely and it's not wobbly at all, and the hinge mechanism is easy to operate.
The keyboard is very responsive and comfortable, with short travel between keys.