I do most of my music listening in the car and I don't have unlimited data, so I use the GPM "pin" feature (localize to SD card) on my phone. At home I stream everything, either from phone, tablet or PC.
More importantly, for me, the GPM service has completely changed the way I listen to music. I never buy albums anymore, I pay $7.99/month for the All Access service and I can listen to anything I want. It's made me a lot more adventurous about trying out new stuff, if I don't like it, I remove it from my library, no harm no foul, instead of $10 down the drain for something I'll never listen to again. I'm hearing a lot more music and spending less (well maybe not, since the less we spend on CDs, the more live shows we seem to go to
). And they seem to get new albums up on the servers pretty much the same day they come out, so I get to hear new stuff right away. I love it!