Giovanni Pierluigi da Palestrina - Hodie Christus natus est 

Agree, but I guess the Choir of the Sistine Chapel can be presumed to interpret the music as intended, as it was written for them. The English and Roman choral tradition are very different as regards balance, treble in particular. That being said, however, the Choir of Westminster Cathedral was formed to try and emulate the Roman style, which attracted a number of interested listeners, Benjamin Britten amongst them, who was so impressed by the different sound he wrote a Mass for the choir. I'm pretty familiar with this setting of the Mass and its motet, and I also have a recording by Westminster Cathedral which was made in the 1990s. As such I find the performance of the Sistine Chapel Choir in this clip contrived, with dreadful suppression of phrases and tempo, which doesn't sound right at all and the music is perhaps rather subjectively interpreted by the Director in a corny manner for dramatic effect to reflect the season. However I would reserve judgment based on the possible positioning of microphones within the Basilica. I have heard the the Sistine Chapel Choir perform live and they have just released a few recordings and the sound is sublime. Therefore benefit of the doubt and let's blame the dodgy sound equipment.