Anyone used the digital pens -logitech io or livescribe?

I about to replace by tablet pc (old and dying) and was looking into the digital pens. Has anyone used them for sketching and to what capacity? I know it wont replace a tablet/wacom but its another tool for designers to use.

I took a class at Techshop and another guy had oneā€¦ it was pretty amazing. He had his pen recording audio of what the instructor was saying and then to playback, he just touched the pen in the area where he had done a sketch and the audio was played back (from the moment he did that particular sketch!)

perfect for doodling in meetings and never missing a comment! or maybe holding someone to the real description of what they originally asked for