Definitely recommended, as everyone above is saying. I'll add in a few things though.
The quality of the music is great, it's MP3 quality. However, if you're using it a lot on your phone or iPad or whatever, remember that it does use a lot of data. If you're on 3G/4G and using it a bunch, watch your data usage, because that'll eat it up real quick. If you're somewhere you have wifi then that obviously isn't a problem. The app's interface rules as well.
Pretty much all of this. It's easily worth the $10 a month.