I enjoy Bach's organ works on occasion, but 20 hours would be a bit much for me. A more selective collection with excellent performances and sound is
Hurford's 2-disc set .
As far as the BIS set, I'm not familiar with it, but it's of course nothing unusual for older recordings such as those to be transferred to SACD. What is unusual is BIS's rather creative and generous use of the available SACD room, as discussed on their site. The room for at least seven SACD channels(e.g. 5.0 multichannel plus 2.0 stereo)is available, so for stereo material alone about 3 1/2 times the usual length can be provided, hence the four hour discs. Applying DPLII, etc. to the stereo analog outputs generally provides a very helpful spatial effect.
