According to Farhad Manjoo of Slate:
The Surface’s shortcomings are puzzling. Microsoft has been working on the technology in this device for years. When it decided to create its own hardware, it had to have known that making a good first impression against the iPad would be the key to the Surface’s long-term survival. The Surface is also the most celebrated home for Windows 8, the touch-friendly operating system that Microsoft is hoping will become a big hit on tablet machines. In other words, a lot—for Microsoft, perhaps everything—is riding on the Surface. So as I used it, I was nagged by a recurring question: Why is the Surface so bad?
The first problem is speed. Everything you do on the Surface takes more time than you expect. When you load an app, switch between apps, launch a Web page, go back to a previous Web page, check your email, and do pretty much anything else, you’ll find yourself waiting a half-second too long. This sounds like nothing, but when you compound that time time across every action on the Surface, the wasted half-seconds add up to an annoying trudge.
It’s not just the extra time that kills, but also how the tablet clues you in to its slowness. The surface is littered with little visual bugs that make you think the thing’s broken. When you pinch-to-zoom in on a Web page, the text first shows up looking jagged and low-res; after a small wait, it gets sharp. Every single time you go back in the browser, you’ll see the previous page grayed out; it takes a split second for it to light up.
When you switch the Surface from portrait to landscape mode, its interface doesn’t switch immediately. There’s a half-second where nothing happens, enough time to make you wonder if the switch registered the orientation switch, so you begin to turn it back the other way just as the screen flips to the new orientation. And when the screen does eventually flip, it’s not as smooth as the iPad. Instead the Surface’s screen simply quick-cuts from landscape to portrait and back again, and while that gets the job done, the transition feels less than elegant. And then there were the times I found myself tapping the Surface like a madman, because I couldn’t tell whether it was just responding slowly or whether it hadn’t even noticed me. This happened often. It wasn’t pleasant.
I know it's his opinion, but this guy's reviews always leaves me with the impression he's trolling.