The Clerks' Group have made dozens of really good recordings over their distinguished career (now well over fifteen years) and this stands with their best, I think. If you know their outstanding performances of Ockeghem you won't be disappointed with these two Requiem masses from two composers of a slightly later generation. Of the two, I would say that Pierre de la Rue's setting is the more rewarding, but both are excellent and I listen to them often and with great pleasure.
The singing is uniformly excellent: expressive, sensitive to the text and technically faultless. The sound made by the ensemble is very lovely, I think - not perhaps as smooth and polished as some ensembles, but full of character. The de la Rue Requiem has a particularly rich sound because of its low pitch, with the basses (including Edward Wickham himself) plumbing spine-tingling, almost Russian depths. It's fabulous. A very warmly recommended disc.
(You may also be interested in two other wonderful recordings of Pierre de la Rue's other masses, by Henry's Eight La Rue: Missa Cum Iocunditate, Motets
and by Amarcord Incessament
. They are among my favourite discs.)