That's a question that I have been asked many times and that has been answered wonderfully at Pocketeables.net
Since many prospective UMPC buyers want to know how readable a particular device's display is outdoors and in direct sunlight, my husband and I headed to Kawaikui Beach Park in nearby Aina Haina this afternoon to find out. We stacked my HTC Shift, Willcom D4, Sony Vaio UX180P, Fujitsu U810, Kohjinsha SC3, and the Gigabyte M704 I have on loan from Direct From Japan in a travel bag, cranked up their screen brightness levels, and set them up on a picnic table. Have a closer look below.
In my own experience none of these devices compare to a Fujitsu P1620 or P1610 outdoor screen.