I love this disc. I don't always find Dufay easy to listen to, but this is a rich, moving and satisfying performance.
Dufay's music is from the mid-part of the 15th Century and so can have a spare, even austere sound to the modern ear. This can be very lovely, but in some recordings I find the spareness slips over into bleakness which can be tough going for the duration of an entire mass setting, say.
I think Diabolus in Musica get this just right. They bring a warmth of sound and lovely, full resonance and warmth of sound to it which, combined with a sedate but appropriate tempo, makes the music glow while never slipping into blandness or losing the music's sense and structure. Technique is excellent, with impeccable intonation and a lovely fluency of line. They sing at a lower pitch with countertenors taking the top lines, which emphasises the bass lines beautifully, and the whole thing is a real pleasure to my ears.
This is one of the loveliest and most accessible recordings of Dufay that I know. Alpha make their usual excellent job of both recording and presentation, making it an all-round gem, I think. Very warmly recommended.