(with apologies to Cato the Censor)
Whatever that stuff is, it's not music. It's anti-music. I have never heard such damnable (I speak advisedly) tripe in my life.
As our choirmaster remarked about Haugen's "Massive Cremation" - "The first time I heard it, I said to myself, 'it's absolutely horrible, and everybody is going to just love it.'"
I like the St. Gregory's Hymnal to sort of ease people into the chant. It's the proper Graduale, but transcribed into ordinary staff notation. Once you have that mastered, you start handing out the original Solesmes notation.
I of course had never seen neumes until I converted -- but it is not difficult to learn. Of course I could read music about as soon as I could read print (mom was a prof in the Music Dept at GA State Univ, teaching "Music and Movement" i.e. teaching singers how to stand on a stage as though they belong there). So I don't know how hard it is for non-music readers. It may actually be easier to learn it cold, because the neumes look suspiciously like ordinary staff notation but function differently.