Yes I own a copy of the KBFH and indeed it is better sounding. I'd agree the quad fold-down concept they conceived was oversold. It would be great to get a true stereo mix but they didn't seem to want to spend much on any catalog upgrades. I remember being so excited to finally get a DVD of the Manticore TV Special only to be let down by a bad film transfer with scratches and a weak mono soundtrack.
I met Bill Hough (designer of the live quad PA configuration) at the Feb. 21st, 1974 concert and he told me "there's a Scully-Metrotec multi-track back stage recording every show." If that was accurate (and the other shows were engineered well) they should've had several more shows to choose live album tracks instead of using mostly the Anaheim show of Fed. 2nd. Darrell Johnson @ JVC CD-4 Cutting Center (Los Angeles visit) told me personally that he couldn't cut a stable CD-4 master because the quad master tapes "were engineered by chimpanzees." Thus we got only the triple Q8 tape set (with Quadradisc logos), and no quad vinyl version.
Remember those 'From The Manticore Vaults' CD box sets about 15 years ago? The allure of live shows is quickly quashed by the obvious weak bootleg quality throughout. It baffles me how Genesis and especially King Crimson have released tons of great quality live material whereas the same thing from ELP is so scarce. If ELP (the band or it's label at a given moment) was looking to cash in (witness the Manticore Vaults where quality was secondary at best) we would have seen other great live releases years ago. They either don't exist or there just isn't any passion to follow through on it. [Steven Wilson got virtually no input or feedback from the band or management on his ELP 5.1 mixing projects]
We're so far down the road now, there is only a fraction of the interest in the band's catalog these days. Breaks my heart, but the memories of witnessing that show will always be strong.