I'm at my desk 80% of the time, plugged into my 27" monitor, with an external keyboard and mouse, the Surface 2 Pro would be just fine, basically no difference compared to using my Lenovo 12.5" or MB Air 11" (though the Lenovo was significantly cheaper at $700).
On the go would be the biggest difference, and though I like the idea of the Surface 2 Pro, Microsoft has yet to convince me that it would be a better device than either of my current machines.