To me, it seemed to be a perfect match of players and material.
The music was all bossa nova, and almost all Jobim, with the exception of three tunes by Oscar, one Bonfa piece, and a bossa/novelty "In the Mood." The duo played arrangements originally written for Castro-Neves' 6-piece band; this gave a sense of arrangement, but with a greater sense of communication between musicians, and a greater spontaneity, than we might have heard from the full band. That is, both guys were figuring out how to cover what was important to the arrangements, and then delivering it to the audience.
Here's a Youtube clip of Oscar doing Waters of March; here's one of She's a Carioca.
There are quite a few Youtube videos featuring Gary Meek (a lot of fusion, as a sideman with Jeff Lorber, Dave Weckl, etc.). None of it sounded anywhere near as good to me as he did in person, with Oscar, playing Brazilian music.