I hate Loreena McKennitt's version! Way too slow. Check out Nowell Sing We Clear's version, even if they only chose to sing a few key verses. Chappell (Popular Music of the Olden Time, 2 volumes) has many, many more verses.
I sort of sing it, and we even tried working on it as a performance piece, but sung at tempo it's a lot of work, and the accompaniment is a bear, too. I like it a lot, and we really need to start working on it again and add it to our mid-winter repertoire.