Pandora Versus Spotify
Pandora & Spotify both have free versions available but those have limitations. Now when it comes to subscription Spotify is twice as much a month as its competitor Pandora who charges $4.99. Now the services are very different so don't go thinking Pandora is a better value just yet.
Capability of Spotify
In this section I will cover what a paid subscription for Spotify includes. Spotify allows you to listen to the songs of your choosing at will. You can make playlist(s) to shuffle or just search & play individually. A radio service is also included with artist radio stations. For example Wiz Khalifa radio. The problem with the radio of Spotify is that it is only artist radios, none for songs & you can't shuffle your stations together. Now if you wanted to go with free Spotify you can only shuffle your playlist, not play individual songs at will.
Capability of Pandora
Pandora does not allow you to play individual songs whenever you like or at all. With Pandora you create a station or choose one already made based on a song or artist. Pandora then plays songs that it thinks you will like. I must say it is so accurate it's scary. You can further fine tune your station by giving songs a thumb up or down, & adding other artists/songs. You can also shuffle all your stations together unlike Spotify. If a song comes on you don't want to hear you can thumbs down and it will change or you can skip it but you can only skip so often. Now you have even less skips if you don't pay for a Pandora subscription aka 6 skips in 24 hours.
And The Winner Is...
In my opinion Pandora is the best and I would get that if you are only going to get one. However if you can afford it and think you'd like it, I suggest getting both as they each have their pros and cons. I like Pandora because it knows me very well and surprises me with new music I like more often than not. Whatever you choose enjoy, I know I do!