The systems that rely on reflected light do look best in direct sunlight. The original Game Boy, Game Boy Advance, Game Boy Advance SP, Game Boy Color, even the first model DS! Note that the DS Lite and GBA SP with backlight are almost unplayable in direct sunlight. The Game Boy Micro also fails.

When I was heavy into the DS, I used the original DS for this very reason. Most of my playing was done outside.