Choice is great, and choosing your own music streaming service is great too! Unfortunately, this choice creates difficulty in sharing music with those who don't use your service.
Now with Convertify, just copy the link to music or playlist your friend sent to you from Spotify or Apple Music. Open Convertify and it will do the heavy lifting to convert that playlist, song, artist, or album to the opposite music service!
Convertify is open source, so get to converting today.