The 840 is my first touchscreen bike computer & that's a great thing until it isn't - I've noticed the screen will pick up sweat drops as taps or swipes all the time. Usually it'll just think I'm trying to rearrange the screen, but occasionally I'll see it in a random menu. Just a hassle for the most part but I could see it deciding to wind up on the "stop course" option if I don't catch it.
I'd like to have the option to disable touch during an activity for the series. It should have minimal impact on function since we still have all the buttons that the non-touch series has.