Warner Crocker at gottabemobile.com has an update on his Thinkpad X61 escapades. Specificially relevant to your truly are his comments on the screen:
I’ve already commented on how much I like the brightness of the screen. And I have had a chance to view it outdoors. (Still no successful way to take a picture of this, sorry.) It is readable in outdoor conditions, but the screen brightness needs to be turned up, especially on bright days. That said, the screen collects dust, grease, and oils from anything that comes in contact with it. After using it in Tablet mode for any length of time it can be quite covered with residue. What I’ve noticed that I find troubling is that this residue does cause the stylus to drag a bit as it passes over a dirty area. And if you take the X61 outside the residue shows up as a white chalky looking mess. This seems to defeat the idea behind SuperView in my mind and I find it troubling. I’m not sure what the best method to clean the screen is, and I worry about using any cleaning solution on it until I get some word about what is recommended. Some of the smudges and residue can be removed with a dry cloth designed for cleaning screens (like the ones by 3M) but in some cases it still leaves residue behind. I’ve also discovered that if, on a hot day, any of the residue is still moist or damp, it just gets smeared around if you try to clean it. I have more success if the screen is completely dry. The real plus of the SuperView technology is that the screen is easier to read under fluorescent lighting which is what we have in our rehearsal hall. This is a big plus for me. [emphasis mine]
He later adds in a comment,
My personal tastes here, I would not call this an indoor/outdoor display. The viewability is better outdoors than screens (like the x60) that don't have the SuperView Bonding. (Look for other posts on that on the site.) But it isn't designed for outdoor use in the context that many think of has indoor/outdoor. [emphasis mine]
Still no clear comparison with the MultiView outdoor performance, but it helps. Note cleanliness... I suppose you would want some sort of plastic on top of the display if possible.