People are using the surface primarily without a mouse, the way a tablet is supposed to be used. Yet there's still so many tiny touch targets all over the place when classic Windows stuff pops up. I cringe when I see video reviews of people trying to laser-tap these and miss a few times until they get it.
The layout also limits the space allocated to the app's title. When scrolling though the top paid apps, it seems it cuts off the title at 7 characters. Basically, almost every app ends with "..." due to space. This is terrible.
The card view is slow, and my App Store crashed once I reached search result #100 (I was searching for my own app). I'm on a 4S, which should be albe to handle the load.
They did introduce the "Related" tab within an apps page, but I'm curious to see how that affects sales after a few weeks.