Funny, while POD certainly is a spectacular date -- I must say that in the corner of my brain that it occupies, I often associate it as being as much an Eric Dolphy sort of date (for me, Dolphy dominates the proceedings), as Hill's. Early, early on in the first half-decade of my first jazz listening (mid 90's), I even filed it under "Dolphy" in my collection.
While I love POD, I think it's elevation (in most camps) as being almost THE definitive Andrew Hill date seems a little off to me. I'd be more likely to nominate "Black Fire" for that. When I'm loaning out Hill CD's to someone, I usually give folks "Black Fire" and "Passing Ships" to start with -- as (what I feel) are the two best examples of his early and later (60's) BN periods. POD does have numerous AMAZING performances -- but so does Black Fire, with the added benefit of (what I think) are stronger tunes (compositions).
I heard Andrew's quartet at the Iowa City Jazz Festival in 2003 - one of the most memorable live dates I've yet been to! (Along with Sun Ra, Sam Rivers, and Grachan Moncur)