According to Songza, all of its playlists are "made by music experts," which I think offers a clear and significant benefit. Since playlists aren't algorithmically programmed, they are more likely to come in varieties that aren't found on other services like Pandora. Take my "St. Ides Sippin'" playlist. It is a subtle yet noticeable departure from the more generic '90s Rap playlists that are available elsewhere. While nuanced variations like this might not be achieved by an algorithm, they certainly are by Songza's experts. And it's because of this unique variety that Songza is able to provide a soundtrack for just about any activity or mood.
As with Pandora, you can vote songs up or down as you listen. This helps the app get better acquainted with your musical taste so that it can provide better playlist recommendations later. You can also skip songs while you listen, but only six times per playlist, per hour.
One of the best things about Songza is that it is completely free of commercials. This is a major selling point, considering the frequency of annoying audio ads on Spotify and Pandora. There are, however, small display ads on the app, but these can be ignored easily enough.
As for sound quality, Songza's was clear and offered no discernible distortion. The app did, however, suffer from some minor lags as I tried to quickly swipe between screens and shuttle between different menus.
A few bonus features worth mentioning are an integrated Share button for sharing song data with friends and a Shopping Cart button, which leads you to the track on Google Play if it's available. What Songza doesn't offer are links to supplementary information about currently playing artists and tracks. These would marry nicely with the existing service.