I haven't heard anything good about the sound quality of the official JB Live releases, perhaps that changed with the deluxe edition. If you want live buckley superior stuff can be found on the many audience recordings.
I would definitely get Grace Legacy Edition, the sound quality is top notch. It has key tracks on the album missing from sin-e and the second disc is very sweet. The bonus material is on par with the album sq wise for the most part, the version dream brother on it is to die for, though it is bested in my opinion by a live performance he did in ausie land, and it has some smokin' good covers like Screamin' Jay Hawkins "Alligator Wine" and Nina Simone's "The Other Woman" which he liked to perform live.
Get it, you won't regret it
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