It's nice to see a legitimate release but the "unissued" material actually seems to be a rehash of Boris Rose dates that have been endlessly bootlegged. IMO, the issued quality has not been bad. I would be pleasantly surprised if the new Fantasy release had significantly improved sound. The link lists 5 tracks labeled "enhanced".
The November 18, 1955 Steve Allen date - "Max Is Makin' Wax" and "It Never Entered My Mind" - and the December 8, 1956 Blue Note (Philadelphia) date - "Tune Up", "Walkin'" and "Four" (all of 1 second for "Four") - were both issued on Yadeon 502, one of Rose's only cd issues. The sound is a little better than the private tapes that were circulating at the time. AFAIK, the video of the Steve Allen performance was destroyed years ago (this is in Porter's chronology).
The "Four", "Bye Bye Blackbird", "Walkin", and "Two Bass Hit" date is a broadcast from the Cafe Bohemia on May 17, 1958. It is not the original Davis/Coltrane quintet. Bill Evans is the pianist. Rose issued this on Chakra TH100 and, again, the sound is reasonable. This date is also on the Jazz Band lp's and cd's.
I'd love to find out that Prestige has better source material for these sessions, as turned out to be the case with the Coltrane Half Note material, but I'll wait and see.
The "enhanced" tracks look like they were taken from these same dates, i.e., "Max Is Makin' Wax", one of the "Walkin'" tracks, and "Four".