The first disc is a half-hour recording made the day before the Pixies recorded Come On Pilgrim; Black Francis went over to the producer's house to play the songs on his acoustic guitar as "audio notes" for the studio session. They're largely amazing, and for some reason the asides ("And then here's where the bass would go...") don't break the solidity of the performances. More than with most demos, demystifying the songs doesn't make them less, uh, mysterious. I hadn't realized before how much Francis's early vocals resembled Gordon Gano of the Violent Femmes.
The second disc: Pixies songs re-recorded with the Two Pale Boys last year. Black worries in the liner notes that they're travesties. The music, at least, is respectable; it sounds like a less-artificial Residents, not like Black's tepid solo albums. But some tracks work (a little) and some don't at all, for two reasons... first, the meditative mood of these re-recordings has limited overlap with the songs' emotional tone. I once ate a fudge brownie with guacamole on top to see what it would taste like, and you know, it didn't ruin either flavor as such, but it wasn't good either, and in retrospect it's hard to see what I thought, at best, was going to happen. So there's that.
The second problem is that Frank Black sings some of his old songs like a kid who's bored senseless with the Pledge of Allegiance but doesn't want to get in trouble by changing the words. He speeds up, or hangs on to a syllable for an extra fraction of a second, or changes inflections without creating a coherent new reading of the line. The songs where he does that, I can't listen to at all. The others... probably worth hearing twice, and that's it.