In terms of ergonomics and usability, the Cirrus developers have taken on a difficult job, and while they've done fairly well, I don't think this unit is quite ready for most users. The magnesium and ABS plastic case has nicely contoured edges that make it more comfortable to hold, and the bottom corners are covered in rubber, which helps keep the unit from sliding around when it's on a desk or its porticle stand. The weight, as I've mentioned, is its chief drawback. Your arm and elbow are going to get tired really quickly, although it's kind of nice when you hold it on your lap. The touch screen is very reflective, and in an office environment with overhead fluorescents, there was a tremendous amount of glare and reflections that cut badly into screen visibility.
Usability is another area where a lot of work has been done, but a good deal more is needed.
There's a big, round button at the top of the Cirrus that was designed to function as a right click. It wouldn't work for me. A mouse-button icon on the desktop was mysterious and didn't seem to do anything except highlight different buttons on its depicted mouse. In fact, after carefully reading the user's manual that comes with the device, I was dismayed to find statement after statement about some function or feature being a known problem and not yet working. For some, possible fixes were outlined but not guaranteed to work.