I enjoy works by Part and John Taverner in a soundtrack-y sort of way, but they make pretend ancient music without the fire or the earthiness of the real thing. It's very much of a piece with the social positioning of the contemporary Orthodox faith, to which both men adhere: a veneer of pleasing ancient ritual plastered over modern convenience. The problem I have with it is that it takes on a very narrow range of medieval aesthetic elements (specifically, the ones most familiar to us from film scores and occult bookstore muzak) and crams them together into a pleasant but directionless collage that makes for great sonic wallpaper, but not much else. It's better than 99% of what's out there, but Burzum comes a lot closer to the actual spirit of the ancients than this sort of commercial necromancy ever could.
There are so many high quality recordings of actual ancient music that it makes Part seem a little unnecessary. I'd certainly rather listen to Tabula Rasa than most modern academic music, but I'd rather listen to Dead Can Dance, or better yet, performance troupes specializing in medieval and Renaissance music performing actual period pieces than either.