I agree with GordonW's rankings.
The HPM's and the S's are great sounding speaker systems.
The early/mid-70s CS-63DX, CS-99A, CS-88A, and the CS-77A have a very nice sound, a bit down on bass from 40 Hz, but boost the bass control and they respond very well. Anyway, in days of vinyl there wasn't much really below 40 or 50 Hz, so that doesn't really matter. The old CS's really shined in the mid range and treble, sweet and accurate sound.
I had the CS-99A and CS-88A and loved them and pounded many a party with them.
But Pioneer really made a leap getting Bart Locanthi to leave JBL and design a new series for Pioneer. That was the HPM series.
While Pioneer owned Phase Linear, they produced a small series of speakers. The two top line models had Pioneer Japan analogues, and then the "baby" P-530, a classic 12-inch, 3-way system with speakers that seem to be early TAD drivers (TAD division was formed around then).