Well, I've used my new Garmin C320 for a few trips now and thought I'd report on my experience.
First off, let me say that this unit is very easy to use. Perhaps it doesn't have all the bells and whistles of some of the more expensive units, but it does the job of getting you from point a to point b and helps you find every restaurant, shopping center, hotel, gas station, attraction, bar, theatre, golf course, library, church, ATM, school, hospital, airport, car wash, etc along the way.
While the screen is very clear, sufficiently large, and has high resolution, it is true that in direct sunlight, it's hard to see. You need to get just the right angle to avoid glare. This is probably the biggest drawback. At night, or with overcast...no problem.
The voice announcements of when and where to turn are loud and clear and at just the right intervals.
The accuracy of the unit is amazing. Seems to know where I am within a few feet.
There is an option of "shorter distance" or "faster time." When I chose faster time, it took me down roads with traffic lights. The same destination with shorter distance took me to the highway. In fact, the faster time setting took longer. Not sure what's up with that.
The suction mount on the windshield works well.
That's all for now. All I can say is that it is a very useful toy. Never have to worry about finding a street or getting lost again.