I was lucky enough to pick this one up a couple of months ago. It's a little-known masterpiece, in my opinion.
Yep, I've got a Pacific Jazz mono copy of this one. Really like it - obviously influenced by the Miles/Gil albums but with a unique West Coast feel to it.
The Al Haig 'Will O' The Wisp' according to my records (ie. the Charles Fox/Max Harrison book, who rated it one of the 'Essential Modern Jazz Records 1945-70) was issued by Counterpoint in the US, I'm not sure re: Esoteric (probably very likely that this was the first issue if so). I have a UK LP issue whuch was on Xtra, one of the labels run by Transatlantic which put out Prestige material in the 1960s.