Surface keyboard might be just below average

Business insider had a chance to play with it and fomr what it seems, I'd rather just use touch input or buy the second keyboard.

At the meeting with MSFT [Microsoft] execs, we were able to try the Surface touch keyboard (we weren’t at LA launch) and also use it conjunction [sic] with new Office (RT- version). All works well. The keyboard is responsive and natural (same size as laptop keyboard), with only downside being there is only slight raised delineation between keys, meaning you have to look at your fingers while you type. With short words, we were able to type accurately, although longer words were more error-prone.”

So now it all comes down to thickness vs. functionality. I would have bought the thicker keyboard anyway but it's disappointing. Hopefully, they are still working on that