I bought this last year on the recommendation of a friend. It is my second Bach Organ Integral, and years ago I bought the mono set from Helmut Walcha on the recommendation of the same friend.
The Walcha is a wonderful and somewhat incomplete set, and it is lovely to discover new gems in this cycle from Alain.
She is poetic compared to Walcha, but both sets are involving to the highest degree, and if forced to choose now would suggest Alain as the recommendation for a first recording, and follow it up with the old Walcha set later on if someone wants two different recordings.
The recordings are lucid and clear, which is very important for the counterpoint to be followed with ease, so that Alain's poetic musical readings are beautifully presented. And so for once wonderful music making is presented as well as the music is played.
I cannot think of one weak link in these performances, but a high point is the Leipzig Chorale Preludes, and another is the Schubler ones as well. After the very direct way of playing that Walcha presents the music with [my friend described it aptly as Mondrianesque], I found MC Alain delightfully more flexible, though never at the sense of rhythm or pulse, and really both sets bring out the wonderment in it at a very human level. I was considering getting the later Walcha [stereo] set, but because of the Alain set, I simple bought Walcha's recording of the Art Of Fugue. Later I was given the LPs of Alain's recording of that from the early 1970s, and this is another pinnacle of Bach Organ music performance in my view.
Anyone who loves Bach's music should snap up this Alain set in my view.