Coverage is getting better all the time, but it still is very poor in many rural areas. I looked at 5 or 6 states where I have toured and it was pretty worthless in the rural areas for the roads I want to ride on tour .

Edit: With a little more checking it looks better in some areas. It is worth using where available, but where coverage is spotty I would pass. I'd rather not pick roads based on whether they were covered by street view or not.

OTOH, where it does cover it is really nice.