there are a couple of threads about this subject in this forum, particularly THIS ONE.
I have gotten used to using my Garmin 800 on 200k's, but the upcoming fleche will be the longest ride where I cared about it functioning. My 800 finished the last two days of Endless Mountains in my drop bag since I couldn't keep it charged for some reason. Knock on wood, I haven't had a white screen in a while.
I have a friend with the new Touring model and he hasn't gotten the hang of it. Lots of lockups and white screens.
I think it works better if you only display maps sparingly, any comment about that?