This is the first Dalgliesh novel I've read - I have a feeling I did once get through An Unsuitable Job for a Woman, so not quite my first P.D. James. (Interestingly, the two books share the theme of the detective being called in to investigate the possible suicide of a young man by his distant, rich, estranged father.) I very much enjoyed it, especially in contrast to Little, Big which I was slogging through at the same time. Of course, the whole thing depends rather a lot on hidden coincidences and secrets (the bit about the consecrated wafer seemed particularly unlikely to me), but it is entertaining and I found the resolution at least psychologically consistent with what we knew of the characters.
The book is set in an obscure High Church Anglican seminary, and there is a certain amount of reflection on the current state of the Church of England - though perhaps it's more that she is doing a conscious (and at one point completely overt) riff on Trollope.