I think your review was spot on and only got a little muddy when trying to classify the device for comparison. Is it a tablet, or an ultrabook? And your conclusion that there are too many compromises either way really depends on the user.
In truth, the Surface Pro is the world most powerful production tablet. As a tablet device it has a stunning everything except native app market (which it doesn't need since it runs millions of Windows apps natively) and poor battery life. Poor battery life is the trade off for the power it brings to bear. I know a lot of people who would trade battery power for productive power.
That trade-off would be easier to accept if, as you mentioned, it had a docking station. This is key and I hope MS or a 3rd party will create one. The criticism that it can't be used on your lap, however, is bogus. Try the on-screen keyboard. I wouldn't want to write a novel with it that way, but neither would I want to write a novel with a laptop on my actual lap. It works fantastic in portrait mode too.
Keep Up with TechRepublic