So far besides the Adam, this little tablet that will fit in your front or back pocket can be read outside. Polorized glasses are a no-no with this tablet. It just needs an anti-glare screen protector and it would be really, really good for outdoor use/reading.

Here is a photo in direct 9AM sunlight, it was also clear with no clouds, next to a Motion LE1600 with "View Anywhere" screen. Photo was taken with Motorola Droid X camera. In person it was easier to read the Flyer than the Motion with outdoor screen. As long as the reflections were adjusted properly.