[wakeupcall]

If that matches my experience, outdoors helps a bit, but not much. Overall you get better contrast and brightness, but the fact that the background is "gray" and not white becomes even more obvious.

That being said the rm3 is usable without backlight indoors if the place is decently lit (for example, in most offices), but requires some backlight otherwise. The rm2 is usable also in poorly lit conditions.