Some services let you listen to the world others focus on the niche. What's your listening preference? Do you like to explore or are you happy with what you know?
Check weather the service lets you save your music for offline listening. Do you mostly listen at home, at your work computer. Or are you more likely to want to listen on the go?
There is nothing better than to pick and mix your tracks together. Who listens to a full album these days anyway? What's next a motivational mix for your next trip to the gym?
Of course it all comes down to money and what the damage is. All you can eat streaming subscription, download track by track? You've got to work out what's the right bang for your buck!