it's a bit hard to tell from that video what the finer details looked like.
i got the impression that the cintiq had better gradation from the video.
another factor, correct me if i'm wrong is the wacom control panel is very adjustable for the user (for the cintiq) and on a tablec pc the wacom control panel if there even is one, practically gives you no flexibility at all.
if i weren't so busy i would do some tests for you.
i am a proud owner of a motion 1400 with 2gb ram and 60gb hd. love my tablet pc, love it.
i wouldn't say it equaled my cintiq 21ux.
would use my tablet for low res work (roughs) and finish it up on the cintiq/desktop.