If I were to get a laptop hybrid, I would definitely look into the Yoga 11s (not to be mistaken with the Yoga 11 Windows RT version). It is basically like the yoga 13 but in an 11 inch form factor which is a lot more tablet friendly, yet would be a perfectly good laptop as well. It is supposed to come out in June. Honestly, if the Yoga 11s was out around the same time as the surface pro, I might of skipped out on the surface pro, because having that laptop functionality is a huge irreplaceable plus. There are times where I really need to use the SP in my lap or where I need a full working keyboard, and that's where you have to trade off with the SP. I could imagine that the SP will still be better at being a tablet than the 11s will however. I've never been a fan of the whole keyboard docking solution such as the Ativ 700t because of some of the drawbacks that come along with it.
Rumor is Yoga 11 will have terrible screen resolution. Don't know what is up with Lenovo and their lousy screens.