I am still charging mine from USB interface, so didn't play for too long.
Again, dimensions are nice - bigger than PDAs but smaller than laptops. Very thin, really cool
and light of course.
Matte finish is great, although it shows you how dirty your hands are very quickly
Interface is very intuitive. Nice to see arrows adjust to all the portrait/landscape/flip combinations. I copied a mix of literature and technical docs, so I'll play with it tonight and tomorrow. As we are reviewing some docs at work, I'll try it for my work as well (including diagrams and such).
So far I am very impressed. To be balanced, there is one minor problem I found with the buttons (Ok and arrows). They are rather close to each other so I already pressed Ok by accident (when I wanted down arrow). Also they require a fair bit of pressure. Since the device is so thin, I try to place another finger underneath when pressing buttons to reduce pressure on the frame (avoid twisting it). It is not a big deal. Just have to be careful when using them. Also I wonder why +/- don't function as page up/down when not using audio functions? If audio is not active then these buttons are disabled, so might as well activate them for page up/down.