I received my bundle Saturday the 18th of May, 2024 I played all four of them twice. The Roberta Flack was by far the best sounding of the four in that not only did it have great quad separation and imaging but the bass was extremely powerful as well as the overall sound of all the instruments including Roberta's voice. I remember this album from the '70s and it is something I wouldn't even consider buying as I was in to War, Earth Wind and Fire, Chicago, the Doobies, and funk and soul music in general. But, this turned out to be a great listen and I could really appreciate the musicianship.
Surprisingly, Hot Tuna was my second favorite sounding Quad, and "Burgers" made me a fan of them. It too had great imaging. I have been seeing this CD all my days and wouldn't think twice about it because I had no interest in it. However, having listened to this Quad, I thought is was very very creative and reminded me of a little bluegrass, rock, and sometimes sounded like the Allman brothers.
Seals and Croft also surprised me. I purchased this for "Summer Breeze" alone, but the overall album was pleasant, and It too, featured great quad and imaging. However, "Summer Breeze" in no way surpassed the rendition done by the Isley Brothers who I feel made this composition their own. Nothing competes with Ronald Isley's guitar solo on that composition.
Finally, I felt Donny Hathaway's disc was the weakest of the bunch, but it was worth the five bucks extra for the disc purchased in a bundle. As someone else observed, this may be the best of the quad bundles. By the way, none of these discs arrived with crack cases.