Got the K480 blue tooth keyboard and it's simply fantastic. It turned the S2 (or any tablet) into something like the Surface Pro or even a notebook. The keys feel great to type on too. It almost makes my notebook redundant.
Cool, it looks pretty nice. I have a similar bluetooth keyboard
I like because it is backlit, but it doesnt have a built in stand
This Logitech one looks like it would be more convenient for switching between multiple devices... I might get one for the office, since I rarely need backlit keys there, and am often using multiple devices. Looks like it might be a little bigger/easier to type on.