I just left a planning session in which we were tossing around various options for Gaudete Sunday--previous post here--when we decided to read through a 3-part version posted by Richard Rice, his own composition from 2004 which he used but hasn't been published.
It is just splendid. It uses the Latin text and sets it to an exciting polyphonic (really homophonic) composition that has a chant-like rhythmic quality (in the sense that it doesn't follow a strict meter). One reason for the flexibility here is that we hadn't had time to work up the Gregorian proper, given all that we had to do otherwise. So this is a rare thing for us: a choral introit. Just the right touch for this singular day.
This is an option for the propers that is often overlooked. Aristotle Esguerra writes in the new issue of Sacred Music that this is a major task for today's composers: set the propers. Not enough people are involved in doing this. We probably need a Chabanel for polyphonic propers as well.
Other current options Latin polyhphony are thin. However, there are English settings by John Sheppard, Henry Purcell, and Anon.
If you sing a hymn not rooted in the proper text, something important is missing.