Google All Access
Not answering your specific question, I haven't tried either of those, but I find myself really enjoying Google Music All Access. It offers everything Pandora does such as radio stations based off specific artists but it also lets you access any song/album you want to listen to at any moment in time with unlimited use. You can also create any kind of custom playlist you want and download music to your mobile device for offline listening (as long as you subscribe to the service, of course). Until the end of June I think it's a 1 month free trial with 7.99/mo. after that. If you subscribe after June 30 I think it goes up to 9.99.