I think the MS tablets (and they are tablets, despite Seigler saying they aren't because they're the "wrong shape") are between a rock and a hard place. On one side, the locked-down, user-friendly world of Apple. On the other, the free, tweaking, custom ROMing world of Android. It's trying to sit somewhere between the two and I'm not entirely convinced that it can.
I think that's kind of the point. Using the iPad is just a cleaner, nicer experience because it's not bogged down with a lot of the desktop cruft.
There is a trade-off between features and complexity, but Siegler doesn't try to evaluate that once in the article.