To be honest I was not thrilled when Google Music had a major update a few months back. They broke integration I had for playing a playlist. It would open the player and just sit there on whatever I was listening to last. Very frustrating. It just ignores the playlist in the intent completely. I tried Winamp which did launch playlists. I also have Amazon MP3 because I use that to buy music mostly. Having the 3 players is a problem. If I launch a playlist with the default player, or send the play command generically from the app the 3 players all fight for who will respond. The results vary and are inconsistent each time.
Finally one day I figured I would try Google Music again. I created an instant mix starting with one of my songs. It worked very nice. So, I configured A2DP Volume to launch Google Music (not a playlist but just open the app) when my car connects. It just open Google Music and waits for me to press play on my Bluetooth car kit (Moto T605). One simple click and my instant mix resumes where it left off. I can use the back and next controls on the T605 to switch or replay songs. It actually works far better than launching a playlist. I don't hear the same songs over and over. I can create more instant mixes and have them ready. Before I get in the car I can select an instant mix to match my mood. I keep the phone in my pocket while driving. I never look at it or interact with the phone directly. This is the safest way to drive.
Google Music can play just on-device music, or all my music both in the cloud and on the device. For a subscription fee you can also sign up for unlimited music streaming. Very flexible and very nice. So I went from fighting it and cussing at it to liking Google Music so much that it is now my primary music player. I would encourage others to give it another try. It has improved recently too so it loads faster and seems more stable.
This same approach also works with Pandora. Just have A2DP Volume launch Pandora (the app only, not s station). Make sure you have selected the station you want to play last time you use Pandora or just before getting in the car. Once the Bluetooth connects, just click play from your Bluetooth controls.
