Well, I've now given a first listen to all 8 discs in this set, and these are my first quick impressions:
The standout for me was Disc 7, which is devoted to 3 Herb Ellis-led sessions from 1962. These are uniformly terrific, and include great soloing by Herb, Frank Assunto and Roy Eldgridge on trumpet, Buddy Tate on tenor, and Ray Bryant on piano.
I also really enjoyed the Kenny Burrell-led sessions on Disc 6, followed by (in no particular order) the Ben Webster/Harry "Sweets" Edison session on Disc 8, the Buck Clayton/Marlowe Morris session on Disc 3, and the Illinois Jacquet, Coleman Hawkins/Clark Terry, Marlowe Morris (as sole leader) and Buck Clayton (as sole leader) sessions.
One interesting artifact in this set is a pair of sessions from 1955 led by Buck Clayton and featuring vocals by Jimmy Rushing and Ada Moore. These are a series of 15 short vocal tracks that amount to a kind of humorous boy-wants-girl, boy-gets-girl, boy-loses-girl mini-operetta.
The only sessions that didn't really grab me on first listen were those led by Ruby Braff, which sort of struck me as being of the Al Hirt/Pete Fountain genre. Unfortunately, they take up the entirety of discs 1 and 2. In fairness, I wasn't paying close attention while listening to them, and they may make a better impression the next time I listen (and if I pay closer attention).
Sorry I don't have more (or ANY) detail, but this is all I have time to post right now. On the whole, I'd recommend this set for anyone who enjoys this kind of jazz from this period. There's nothing earth-shaking here, but it's all uniformly well-played and enjoyable music.
I'd be interested to hear what others think.