I’ve been running with my Apple watches for years and love it. I’ve noticed that my S4 has been measuring too many kilometres compared to the measured route. Ran a local half marathon today and around the 20 km mark my watch was 0,35 km ahead. It ends up making a pretty big difference - my watch said I ended at 5:27 / km and the official around 5:35/ km. My goal was to hover around 5:30 as that’s the marathon pace I’m aiming at for the upcoming race so no major catastrophe. But if the watch is responsible for me going over the calculated 4 hours because of bad gps measuring I’m going to be quite disappointed.