Not complaining, because we really don't see enough Perotin, Machaut, Landini or Dunstable -- but it is difficult music based on quite different theories from what we moderns are used to, and it is tough for even very experienced choral singers.
We have done some Palestrina, Dufay, and da Vittoria, others that I have never heard of but which our director comes up with.
Many of the hymns are right out of the Liber Usualis, but then we will add parallel organum parts in fifths and thirds.
I have come to learn how really beautiful and spiritually transporting this music is, especially when sung in the intended context (Holy Mass).