Tom here is my response to your Surface Pro 2 questions.
Let me start by saying this is my first experience in using a touch screen computer and my 'insistence/closed mind' on having a full windows operating system for compatibility concerns made my shopping experience limited to the Surface Pro 2 so that after playing with it for 10 mins at the store I felt comfortable it was worth the go.
Been using it for 2 full weeks in the office in the exam rooms for Amazing Charts/patient charting; it connects wirelessly to the server database and I can appreciate no obvious lag and think it is actually quicker than the laptop I had been using. I also use it to connect to the internet while in the exam room to look up hospital/lab information again quick to connect only hangup is the hospital website traffic(they need better server capacity) and that the hospital software not optimized for Windows 8/touch screen/gesture technology.
That being said AC not really Windows 8.1 optimized either still waiting for a response from Mr Squire on that one would love to be able to expand the fields in the chart but it still doesn't seem much of a problem viewing the fields.
Choosing a field with finger action or the capacitance pen can be tricky if the tabs are small and next to each other; the problem is that the screen starts to read the signal from the pen once the tip is about 1 inch away from the screen so that at times the wrong tab gets selected,that was more of a problem week 1, my pen accuracy has improved and I now keep the point of the pen shielded with one of my fingers as I approach the screen so this week think I have no tab 'errors'.
Using the Metro interface just takes some time(and not a lot of time really), i.e. what do I have to do to get to the programs, close programs, switch between open programs etc. I used the online guide from Microsoft and if I wasn't using the device predominantly in the office for AC/patient charting think I'd use the Metro interface more. I put AC on the desktop portion of Windows 8.1 so I mostly live on the desktop though switching between desktop and Metro is very fast, I think I could put AC on the Metro interface just haven't tried yet.
The keyboard/cover works well, there are 2 options for keyboards one is a smooth surface keyboard, the other one is more traditional with individual keys the latter is the one I have works well even the little mouse pad. I thought I was going to be using the writing on screen function for input but the keyboard is faster.
One 'bug' that has occurred twice in the past 2 weeks is "delayed wake up from sleep" when opening the device from being closed; usually this requires a short push of the on button to 'wake' it from sleep but once required a 10 sec push and once required a reconnect to power supply. I open and close it about 50 times a day so not very frequent a bug. My reading into it seems to indicate there was a video driver change from Windows 8 to 8.1 that is the culprit, could roll back the driver but I understand it is a known issue and will be addressed so I'll just wait for the update.
Hope this gives some insight.