This collection seems to me to be worth buying, but it has its definite strengths and weaknesses.
Firstly, its strengths. (A) Nearly all the performances are at least adequate, and some are very good. In the latter category (I have to be selective) falls much of the singing by Capilla Flamenca, who feature by far the most prominently. They seem to be equally at home both in sacred and in secular music. As regards the latter their main offering is some of Jacob Obrecht's chansons, where they sucessfully capture their spirit (not at all courtly) and came up with some imaginative voice/instrument combinations. On the last disc (Bellum & Pax), there is some superb brass instrument playing. I would also wish to single out the contribution of the vocal group "Vox Luminis" who, inter alia, produce most expressive performances of Josquin's Lament on the death of Ockeghem, and Ockeghem's lament on the death of Binchois. I enjoyed Diabolus in Musica's performance of Dufay'smagnificent Missa Se la Face ay Pale. The all-female group Discantus make some rather anonymous-sounding sacred music by Binchois sound rather beautiful.
(B) There is an abundance of beautiful music, and a very good variety of different genres-I would particularly wish to mention (again I have to be selective) two masses by Dufay (the Sancti Jacobi as well as the Se La Face) and Ockeghem's Missa Mi-Mi. We also have a complete mass by Pierre de la Rue (the Missa Alleluia) which is finely crafted and has a moving Agnus Dei. On the Bellum and Pax disc (which is largely a complete mass made up of individual movements from various composers' settings of the Missa L'Homme Arme) de la Rue's contribution is really stunning. There are motets by Obrecht, Dufay and Pipelare (and others). We also have some lovely short pieces by Johannes Prioris and his Requiem, which all seem definitely worth performing, to say the least. On the first disc there are some good examples of very early polyphony. There are examples of Gregorian Chant embedded in larger works.. There is also a good selection of secular music (mostly chansons by Dufay, Binchois, Ockeghem, Loyset Compere, Josquin and Obrecht). The Obrecht chansons were particularly entertaining. The secular music constitutes roughly 25% of the total.
(C) Overall, there is plenty of variety in terms of timbres: nearly all the sacred works are sung a capella with one or two voices per part. In two motets a boys' choir is used (apparently authentically), and some motets are sung by all-female groups. A huge variety of instruments are used (mostly in the secular works). So plenty of colour.
(D) There is a beautifully illustrated (using art from the period) and a very informative, often erudite, but occasionally obscure, booklet.
Now the weaknesses, which are outweighed by the strengths.
(A) I found the performances by Capella Pratensis of the Missae Sancti Jacobi and Mi-Mi interesting but rather problematic, even strange. They sing the music with a kind of unearthly reverberence, and very slowly. The sound they make I found strangely compelling, albeit rather lugubrious, but the music itself seemed rather to fragment-the emphasis seemed to be (to an unusual extent) on each individual moment, to the detriment of the music's vertical flow. On the whole, I prefer the more orthodox approach of the Binchois Consort (to the Dufay) and the Hilliard Ensemble (to the Ockeghem). Devotees of some twentieth-century music might feel quite differently, and I have to say it was interesting to have a different approach to early polyphony. The duets in Missa Mi-Mi also came accross very well.
(B) I thought the performances of the Dufay Binchois, and Ockeghem chansons were a little unimaginative, in that too much of the vocal work was entrusted to the soprano voice, and also none of these chansons were performed with voices (as opposed to instruments) on all parts, which can be a very effective mode of performance. Having said that, the performances were often quite attractive. The Dufay chansons had drum accompaniment (in addition to soft instruments), which sometimes didn't seem to suit the character of the music.
(C) Busnois, Agricola, and Isaac were all notable absentees in respect of the period covered (it should be noted that the collection doesn't go beyond the period of Josquin and his contemporaries). Disc space is taken up by two masses (by Arnold de Lantins, and Johannes Brassart) which didn't seem particularly memorable.
(D) As the previous reviewer has said, there are no texts. I didn't find this disastrous because most of the music is of sufficient quality to stand on its own merits. I didn't find any problem with sound quality, apart from the fact that some of the tracks on the first disc sounded as though they had been recorded in a very reverberent acoustic.
(E) I would have found it more satisfying if the Bellum & Pax Disc had had a complete mass by one composer (de la Rue?), not movements by several different composers. Possibly I am being a bit puritanical in this regard.
Taking everything into account, I can recommend this collection, which consists mostly of reissues of previous recordings, but not enthusiastically. It could have been better in certain respects (which could have been remedied by rather less reliance on previous issues) and therefore represents something of a missed opportunity.
For a full track listing, please see the very helpful review on Amazon.com