I have a Garmin Nuvi 350, and use if periodically. My problem with it is that it can be set to do this or do that, but it can't be set to use the most common route. It is always trying to save .1 mile here, another .1 mile there, and putting my on heavily traveled city streets, when I would rather go around congested areas. It also seems not to like the most used but still not congested crosstown parkway, but instead routes me on a zig zag course onto and off the Interstate (the Interstate is so congested that I avoid it at all costs).
I wish I could tell it to go from hither to yon, and stay off of Xxxx Boulevard, and to use the parkway when feasible.
-- Regards, Pete snipped-for-privacy@cox.net