OK, the title is opinionated and contentious, but I have a definite question. I know that the title refers to the Bourbaki volume Groupes et Algèbres de Lie (Chapters 4-6), published in 1968, but

who said that it is the only great book that Bourbaki ever wrote?

The only reference I can find is the 2009 Prize Booklet for the AMS-MAA Joint Meetings, where no source is given, but I'm sure I've seen the claim somewhere else.