the "OBC" because it includes Sondheims' beautiful "the hills of tomorrow" songs which bookends the show. also, rich and happy is better than that frank, AND the overture is more complete in the OBC.
the revival is the more "complete" recording, but the OBC is the better one to have.
"I'm an American, Damnit!!! And if it's three things I don't believe in, it's quitting and math."