I don't actually use Vox but as much as I've heard they wanted to Support large variety of Music Formats like FLAC for lossless Audio. So their app can do that. But they won't be able to Play AppleMusic or iCloud Music, the way they it works. Marvis can Play anything Music App can. I hope when you asked the difference you meant functioning behind the scenes. I hope I was able to answer your question correctly.What's the difference between Marvis and Vox?