" I did not find it a good device for sketching; the interface in Photoshop CS5 (my usual painting program)"
When all you have is a hammer....
Seriously, PS5 is what you based a thousand dollar machine on? Considering the plethora of very good sketching programs out there the fact that you used PS5 tells me that you didn't really give the thing a chance, or that your idea of sketching is different than using a pencil and paper. I have a Surface 1 with Autodesk's Sketchbook Pro and it is a joy to work with. Smooth drawing, grea tool set you name it. I hope to get my hands on a copy of Manga Studio, but it isn't in the cards at the moment. Penny Arcade has been drawn on Surfaces for a while now, though I understand that Gabe has had some issues with the SP3. There are plenty of artists out there who are very happy to have an alternative to the side pad and the the surfaces are scratching that itch. Next time you try one, grab some 30 day trials of some software that is actually meant to do what you are looking for, PS is great and all, but lets be honest, it is becomming a backwater in the sketching deparment for a reason.