Gizmodo has done a nice table to show us the similarities and differences of the tablets in the market. Of course, the main focus is the Apple iPad and the HP Slate. Along the way, they added JooJoo Tablet, Dell Concept MID and etc.
Here is the big table that Gizmodo has compiled. I am looking forward towards the HP Slate.
As you can see, nothing is perfect. So, I guess at the end of the day, it boils down to usability and ease of use. Apple has always excel in the ease of use in their iPhone. I am sure iPad will perform the same or better.