My only problem with streetview is that it omits the best cycling roads, at least on the West Coast. I usually figure if it isn't shown, that's a good thing and I should ride on over and check it out for myself. Still, it would be nice if some of those very low/no traffic roads were included. It would only double their work.
Now, Google Maps is an entirely different matter. Where I live and ride it regularly shows roads that don't exist, which is rather annoying when you are assessing just how far on a high-speed shoulderless road frequented by barbarians one will have to ride. It does that one better by occasionally ignoring the existence of roads that do exist.
I guess they get a grade of 99.99%, which is pretty good for free.