My wife and I are thinking of upgrading to the Series 4 but would love for some people who have and use LTE to comment on the quality of it. We are Apple Music subscribers and I am primarily interested in how well the music streaming works, phone calls, etc., when you leave your phone behind. I am a runner and curious how reliable it is if I go for a run without my phone or leave my phone in the locker at the gym, etc. Any feedback?