I bought an Vivoactive 4s for my girlfriend and the función of auto detection for workouts isn't working properly, taking a public bus or metro is counting like a workout, which is very bad because has ruined his metrics ! Has added speeds over 48 Km/h on his workouts ! Also very poor battery life, lots of things are off and with 1 hours of exercise per day is having 2,5 days of battery life. Poor quality !!!!!