Can you say something about the usability in bright sunlight?

I ask because I currently use TomTom Navigator 5 on a Treo 650 and recently got an N800. I was going to upgrade to TomTom 6 but I thought I might prefer a GPS on the superior screen of the N800. Plus, I'm more likely to replace the 650 (to get HSDPA) sooner than I'll replace the N800.

The problem was that I happened to take out the N800 while I was in the car, navigating with the Treo 650. I was shocked to see how hard it was to read the N800 display. Since I was stopped at the time, I could just use my free hand to shade the display, but that is not an option while driving.

I need a GPS that I can reliably glance at for a very brief moment to get the needed info. I can't always control the amount of sunlight in a driving situation. I'm really disappointed by the poor readability of the N800 in direct sunlight.