Much of this music is familiar to me from a decade attending Mass at the Maternal Heart of Mary Church in Sydney. I love how the choir master, Msgr Palombella, describes Sicut Cervus as being a favourite for the congregation to join in (see 3:30). Polyphony doesn’t forbid congregational singing, it just raises the bar.
Also, you might sense a difference with Allegri’s Miserere. They are singing from a manuscript from the Vatican Archives from 1661. This is before that famous high C was added in a later elaboration.
You can buy CDs or downloads from Deutsche Grammophon. I have and I will be listening to these tracks over and over again.