Why would anyone buy a Yoga over the Dell XPS 12 (Updated / Preview video)

The Dell XPS 12 is up for preorder now at 1199, I was about to hit the buy button but I'd like to know from you guys, what design is best?

The new Dell XPS 12 Convertible Ultrabook (via DellVlog)

Lenovo IdeaPad Yoga 13 at IFA 2012 (via LenovoVision)

I think the Yoga a wrong design, having to touch the keys when holding it like a tablet or even worst having the keys exposed to the surroundings (stuff in your table, desk, etc) and having to worry about closing it does not seems like a good idea, the XPS 12 seems to make the transition from laptop to tablet quite better as well and the design seems kind of aesthetically better too, those hinges in the yoga seem quite ugly.

This is my opinion but I've seen a lot of post from you guys talking wonders about the Yoga, so, for you what's better between the two?

Preview Video from laptop magazine:

Dell XPS 12 Hands-on Video (via laptopmag)