I tried using Spotify, but after every song there was an advertisement. Is everyone actually paying for Spotify? Why would I want to do that when I could just listen to my mp3s for free?
I also listen to my own music files ripped from CD. For that, the Sansa Clip used to be great until the headphone connection broke.
I used Google Music for this, for a while at least, but gave up on it when it became clear that it was inevitably heading for the Google Graveyard. I'm not sure I want to bother with Spotify, and I transcoded my FLACs to Opus to put on my phone's SD card. Foobar2000 for Android takes care of music playing now.