My experience has been quite pleasant and has been for others I've seen use it.
Usability studies of this sort almost always find tons of problems in anything that is new. For example, remember the iPad study by the same group?
For the last 15 years of Web usability research, the main problems have been that users don't know where to go or which option to choose — not that they don't even know which options exist. With iPad UIs, we're back to this square one.
But it's even worse, because look at the study participants: We tested 7 users — all with at least 3 months' iPhone experience — but only one was an "experienced" iPad user.
These were people who were well versed with the iOS UI already! And they still found the iPad hard to use! Did they really really find it hard to use? I doubt it. But that's how usability studies work. You have a short amount of time with new technology and are primed to find flaws in it. And your're primed to be unforgiving (just the nature of being in a study).
I recall being in school when cut & paste first started to go mainstream. The number of people who didn't find it or understand it would be considered bewildering now. Now its a common pattern. But it is pattern. No one complained they couldn't find it, but were happy when they did. And taught others.
All these things are patterns. Bring any non-trivial product into a lab: Chrome, iOS, AppleTV, Android, Windows 8, Boxee TV -- you'll find that people will struggle more than you think. But one thing you learn when you do usability work is that there's a distinction between discoverability and usability.
In my experience Win8 has some discoverability holes, but once you learn a few patterns its usability is quite good.
BTW, here's a review of the Surface for real people:
http://betanews.com/2012/11/14/microsoft-surface-review-for-...
His summary? Surface is fantastic. Why the difference? If you are willing to spend an hour using it, rather than trying to note usability flaws, you'll find it a rather nice experience.
Jeff Atwood says, "I'm a little embarrassed to admit how much I like the Surface RT. I wasn't expecting a lot when I ordered it, but after a day of use, I realized this was more than Yet Another Gadget. It might represent a brave new world of laptop design." Jeff is someone not looking to score points by pointing out obscure design issues ala Marcos. He wants a device he can use. I think we'll see for this class of users (which is much larger than the Marcoses of the world) that they'll resonate with Atwood's take (http://www.codinghorror.com/blog/2012/11/touch-laptops.html).