You can learn to use the clearnav without ever opening the manual,
its that easy.

As for power consumption I know my clearnav uses considerably less power than my
old ipaq setup so it is a non issue for me, if you are having power consumption issues you may want to check you might be leaving the backlight on high all the time.

In the US if you need clearnav help it is readily available as there will likely be several others on the grid that can help, lx800 not so much.