Gizmodo posted a leaked internal document from HP comparing the Slate to the iPad.  Click the image to see a slightly larger, more readable version.  In my opinion the only advantage that the iPad has to the Slate is the battery life.  I think the stronger processor, HD playback, port options, and two cameras make up for that though.  Also the fact that it can run a real OS (Windows 7 vs iPhone OS) and the fact that the most expensive one is $600 is very nice.