It is a large ambitious contribution to the art of great piano playing. It is a labor of love and represents a tremendous amount of research and cooperation between many record companies. Rather then representing insanity, it is a resource to treasure.
Yes experts can quibble over who was left out, and what performances were inserted. I do not think such a massive undertaking could have been accomplished without someone being able to find faults. Overall however, unless you already have a monumental collection, (it would have to be almost legendary), this incredible set will give you a rewarding look into 74 of the greatest pianist of all time. You will come away with a honed sense of appreciation for your likes and dislikes. You will undoubtedly become someone who will search out recordings and be able to enjoy them for the rest of your life with a refined ear.
The only negative is this price. I would shop around, as it is daunting to spend 2 thousand dollars on such a collection. Of course you do get 200 CD's. However, the used collections might be good to consider.
Enjoy these masterpieces. I am not ashamed of owning this music as `insane' implies. I am proud to have enriched my life.