Doing a quick search, there are plenty of third-party apps that purport to transfer your playlists for you. You just log into your Spotify and YouTube accounts through their webapp and away you go. I find this kind of service... sketchy, though - you're essentially giving that site your logins/auth tokens for your music accounts. The service is free, so I'd put money on them scraping your accounts for metadata they can sell. And if you've read any of my other posts, you probably know how much this irks me. I value my privacy. And perhaps, you value yours.