I can confirm the dust issue. Its noticeable enough that I can see it when the screen is displaying a black page (the CNN app for instance). The seal on my Atrix is so poor that a very small piece of cat hair got into it! After some strategic fingers presses and air blowing I managed to get it out. Still nothing I can do about the dust particles though.
I gotta say...coming from a Nokia E71, the build quality on these Atrix's is pretty poor. The seal blows, the battery case creaks while you hold it and doesn't really feel that secure. And don't even get me started on the battery life. All the reviews are saying how great it is. The E71 gave me DOUBLE the amount of life with the exact same amount of use.
I want to like the Atrix, I really do, but these negatives are starting to add up.