It really is a marvelous resource for directors who face constant pressure of preparing chants for the Mass. For them, one Gregorian chant per week is as much as their choirs can handle, so for offertory chants and entrances, there needs to be a resource available to provide dignified music in a pinch.
Adam Bartlett and his team are working hard to put together a plainsong Gradual for the year. Others are working on similar projects, including Fr. Samuel Weber. I feel sure that we are going to see an outpouring of these over the next few years – and it is long past time for this to happen.
In the meantime, it makes sense to have the AUG on your shelf. The book is easily criticized for its repetitive modes and patterns. But, to me, that’s not quite the point: these are not to be used for every proper, every week. They work best for occasional use. When you need them, they are there. Even if you use it only once every two weeks or once per month, it serves its purpose.
The additional issue concerns the language, which is not modern. I don’t really have a problem with that at all, and I actually like it simply for the reason that liturgical language should be more elevated that casual speech. It’s primary purpose is not communicative cognition. Even so, I grant that it can be a bit obscure at times.
I doubt many people prepared the Moses offertory this week. In this case, it works really well to do this piece alternating cantor and choir.
At St. James AC, we use the little Burgess Gradual, which is basically the same thing. Yes, maybe it's not as interesting as chant, but we'd rather use our rehearsal time on the Ordinary and the occasional motet, and nobody seems to mind the psalm tone. Of course, then there are the Sundays we spend 50 minutes on the hymns because the boss has a burr up his…
The "but it's the same music all the time" repetitive modes and patterns complaint totally ignores the fact that using these teaches the choir to sing masterfully in unison, which dramatically improves the singing of melismatic chants.
If…repetitive tunes had been employed by the pulp missal publishers, there would be less need for gregorian chant, but since they have implemented continually changing antiphons and no tonal relationship between antiphons and verses, they dropped the ball.
Instead we got the mid-20th century version of Andy Hardy's Let's Make A Movie…Let's Make Responsorial Psalms!
Repetition is so important for teaching singers how to sing consistently.
And what better way to learn the modes?