I agree, this is a great disc, one of the many incredibly pleasant surprises that has come out of AF's quad reissue series.
I think if you've collected quad albums for any length of time, you've probably seen many copies of this album on vinyl and 8-track for sale on various auction and vinyl sales sites. Being issued in 1972 (the first year of Columbia's quad program) it was probably one of the titles that was in print the longest. I always felt, however, that the Q8 of this album was pretty sonically underwhelming (it was issued before Columbia started Dolby encoding their tapes in mid-1973) so it wasn't one that I gave a lot of play to. The SACD presentation of the quad mix really changed my opinion of this album (from 'average' to 'very good'), and I think the mix itself is particularly effective. I love the way the instrument placement varies wildly from track to track - it feels like the quad remix team (Steve Cropper & Don Young) really took some time to think about what type of mix would most benefit each individual track, and as a result you get a really engaging listen that keeps your attention right to the end. Contrast that with something like the 5.1 mix of Steely Dan's 'Everything Must Go', which someone once (very appropriately) referred to as having a 'set it and forget it mix', ie. the instrument placements are the same from beginning to end. I know it's a slightly apples and oranges (no pun intended) comparison, but the songs on that album tend to blur together a bit, partially as a result of the mix.
So in a nutshell, if you like early 70's hard rock (with a hint of the jazz fusion that would characterise Beck's subsequent albums) and wild quad mixes, you can't go wrong purchasing this disc.