Actually, what people should be looking for is not the clarity of the maps, but the clarity of the voice instructions. My old Avensis had built-in SatNav which ran on a teeny mono LCD screen on the dash, but was good since you never really needed to look at it while navigating, the voice directions were clear, making use of adjectives.

"In 200 yards, turn HARD right, followed by a SLIGHT left."

I've had many discussions at work about road maps, sat nav and people being idiots.

I only see the real need for sat nav to do the very last part of a journey. I can definitely get to pretty much all the major towns and cities in the UK without sat nav, or a map, by just using road signs (and looking up where abouts they are beforehand). Getting to an actual destination is where sat nav is actually useful.

I couldn't agree more on that, I do often use it for the ETA reason.

PB : That's very true also, but I don't often want to deviate.