It is an excellent app for finding, downloading, and listening to any song/music you want. Gtunes downloader can preview a song before you download and make sure that it is exactly the one you want and can save it directly to your device memory or SD card. It contains millions of mp3 directories for streaming any artist song.
Yes, it’s illegal to download music from Spotify. So that they can use it outside of Spotify. It doesn’t matter if they are original or cover, it’s copyrighted material.