To quote somebody-or-other, if this doesn't turn you on you've got no swithches! The whole work is achingly beautiful. It was recorded in St. Mark's Cathedral and the accoustics and atmosphere are both stunning. Gardiner has an academic streak, and the insert booklet reads, in places, like a very good undergraduate essay, where he argues about the degree to which the counter-reformation influenced Monteverdi. I'm sure he's right, and his interpretation doesn't sound up-tight enough to be heavily influenced by some kind of post-Tridentine fortress mentality. Gardiner uses these insights to give his interpretation an authentic, oriental feel.
The first time I heard the Vespers, these were recorded by Jurgen Jurgens. I bought it as a boxed set of LPs, many years ago, now disintegrated. Jurgens is much more precise - the plainsong, for example, could have been done in the Cisteine Chapel. I must admit I like Jurgens the best in this particular instance, although his interpretation is probably less authentic. But that's my personal quirk, and Gardiner, as always, is just wonderful.