So if it was going to succeed at something, the most likely outcome would be as a good-enough laptop replacement and a good-enough tablet replacement, even though it would be a compromise as either. Instead, the reviewer came to the conclusion that it was more of a "neither fish nor fowl" product. Having not had a chance to use one myself, I nevertheless suspect that will be my conclusion when I have a chance to try one out.
If Metro apps take off, then in 6 months to a year, Surface could be a completely viable iPad replacement. But right now, you would have to have a pretty limited set of needs to be satisfied with a Surface.
Worse, I've read more than one review claiming that the software is still glitchy. While understandable in a 1.0 product, that's a huge disadvantage when compared to the famous stability of an iPad.
So while I'm sure there will be some interest just because it's a cool-looking product, I don't think more than a small minority of users will find it a realistic substitute for an iPad.