I have an iPhone 5 running iOS 6.1.4. I used to be able to download playlists for offline listening and a song would download in about 10 seconds. Now, whenever I try to download a new playlist it is EXTREMLY slow - I'm talking 5-10 minutes for ONE song. I have a 100 megabit cable connection and anything else I download on my iPhone or my computer works fine so there is no issue with my Internet connection. It just occurs with Spotify.
It really seems that this may have become an issue since the last update as I never used to have any trouble until after the update. As this issue makes offline playlist virtually unusable, I hope it is fixed soon.