@pgaulke60, the musical content of a lot of direct-to-disk LP’s has not been their primary attraction (particularly true of the Sheffield’s), but their sound quality. As J. Gordon Holt once said, all too often the better the recording the worse the music, and visa versa.
D-2-D LP’s have for a couple of reasons long been used as reference material for evaluating hi-fi components. They will not be the limiting factor in the sound a system produces. To reproduce their transparency, dynamics, and true-to-life instrumental and vocal timbres is a real challenge. They all possess a startling "aliveness", a transient "snap" not found in most recordings made on tape (or in digits). It’s easy to hear when a component loses some of that characteristic.
Some D-2-D LP’s are common and not expensive, others rare and not-so-cheap. The For Duke album is, unfortunately, amongst the latter. It took me years to find a copy, and is not for sale!