My daughter got me into this group around Christmas time. It is fascinating to watch them perform. I usually don't go for music like this, but they really can do amazing things with their voices.
I found their Christmas songs' arrangement very interesting. They make the songs rather different from what we used to know, but not necessarily in a bad way. It also fascinates me that they can produce rich sounds with their mouths. It was especially rewarding to see them performing live and proving their quality.