There's a problem where your music will stop randomly, it takes either pressing play a bunch of times, force closing the app or restarting your phone to get it to work again, usually only lasts a few songs though and the problem starts again.
When I went to tmobile I too picked up the M8. Unfortunately, as much as I liked everything else about the phone, I had to trade it in for the S5, for the better camera and the water resistance, both of which are highly needed for my job.
Sprint is absolutely horrible. I have both them and tmobile. Once I get my G2 paid off I will be leaving them and going to At&t. Tmobile I get LTE everywhere, sprint I can barely get 3g in my house.
re: Galaxy S5 Water Resistant?! Maybe "in your dreams" but not mine ;)
I experienced what could have been a nightmare when I dropped mine in the ocean during a drunken stupor chasing a seal. Baby works just fine.