I recently discovered that AudFree Spotify Music Converter can download an entire playlist into one folder. And I can set music to MP3 and FLAC formats.
Yes, DRmare Spotify Music Converter can do it as well.
Among all these Spotify converter tool, I prefer TuneCable Spotify Downloader best. Unlike AudFree, it downloads music from both Spotify app and web player. And Spotify app downloading provides real 320kbps songs. And the customer service is amazing.