This is a fun record, probably all the more so for being a bit unexpected; old-style jazz and blues played by a great band who sound like they are enjoying every minute. Clapton is on fine form, singing and playing well... he always does better when he's part of a challenging project, when someone is pushing him. Good stuff.
Edit, after a few more listens/watches, few more observations. First, I don't get the hate some people have for the sound... it's a live album, it's not meant to sound like it was recorded in a lab. Sounds fine to me.
Second, it does come across as ever so slightly under-rehearsed; good! There are a few moments where things come a halt very briefly, and everyone looks round before carrying on. There's one instance where Clapton finishes a solo slightly before the band expects it, and he's not the only culprit. But does this detract from the fun? not a bit... adds to the spontaneous live feel, if anything. Watching the DVD is worthwhile here, because you get more sense of the interplay between them all. Both Clapton and Marsalis make funny, eloquent and honest speeches between songs, which aren't on the CD.
Lastly, I found it interesting that Clapton started coming out with some very Cream-like licks whenever he was getting into his lead work... and Cream was probably more of a jazz band (live, anyway) that a rock or blues band. I like to see Clapton work hard when he plays guitar, both solos and rhythm. Not because I'm a sadist, but because he's damned good at it. His guitar choice was great for this too, lightly overdriven Gibson... I was dreading the clean Strat approach, but we were spared that!