I first read this at the same time that I first read Nine Stories. Same edition, too, I think. Re-reading it now I feel the same way I did then: it's his best. (Then again, I never got around to reading Roofbeams/Seymour until yesterday. We'll see.)
In my mind it had always lingered as Fitzgerald for the '50s, which is evidently what Salinger had set out to be. Same eloquent and witty delineation of a particular intellectual and socioeconomic set, same urbane and yet not disengaged prose... Anyway, I saw a connection. I know a lot of people do.
What surprised me re-reading it was the spiritual dimension. I feel dumb being surprised by it, since it's obviously the point of the book. And I'm not unsympathetic to the spiritual quest here, as I'm in principle a supporter of the varieties of religious experience. As I get older I'm afraid I'm getting more, not less, materialistic (in every sense), but still: go seekers. (And, when I'm in the mood, go Beats: this book clearly connects Salinger, possibly against his will, to Kerouac and Ginsberg and them-all. More angst and less joy, but same concerns.)
But even now in the full enlightenment that this book is about Searching for Truth and Transcendence, I still think it's the novelistic qualities I love it for. I know a lot of people are rubbed the wrong way by the Glass family, but I'm fascinated by them, which is a measure of Salinger's description and conceptual abilities. He's created some immortal characters here, and he has them say amazing things. Yes, I find Zooey's speeches just the tiniest bit tedious by the end, but overall, this is a tour-de-force of writing.