I've also had no problems with the Edge 820. Battery life is good, I don't know exactly what kind of life I get -- I charge it once a week, depending on my schedule that can be at least 10 hours run time with the screen on the whole time. The touchscreen isn't perfect, but I don't find it to be a big deal.
This was not my experience.
With just a data screen with four metrics displayed the battery only lasted 4.5 hours.
At $400 I expect better.
I admit that I'm spoiled by the $160 Polar V650's spectacular screen.
-Tim-