My biggest question around the S10 vs U2 debate is whether the S10 battery will survive during very long workouts (3-4hr) with bluetooth+streaming+GPS, without enabling any low-power mode features. Has anyone done marathon training with the S10? If my experience with the S6 is any indication, I suspect that it would last the whole workout without any music/podcasts streaming, but I need those and would prefer to not bring my phone along.