If you use Spotify, iTunes, Deezer, Groove Music, YouTube or SoundCloud, transferring playlists between the services is actually easier than you might think.
BUT, if you don’t want to use an online service – there is an app for that.
Enter Stamp. Stamp is a Mac, Windows, Android and iOS app that will do almost everything Soundizz does, but you really need to pay for a premium account (For roughly $16) otherwise you are stuck migrating only 10 songs.
Lastly, if you just live in the iOS ecosystem – there is the aforementioned Song Shift.