Battery life is kind of a moot point in some respects when you consider most units allow you to charge off a USB stick battery while operating. I get that it's nice to have 20 hrs. out of Garmin and that when they start to lose life and they get down to 5-6 hrs., that's annoying. But if your doing a double century, 15 hrs might do 'ya. Touring ?, randonneuring ? and approach to device selection is different.