I am with you. I started with 3, 5 and 7. Was so pleased, I bought all of them. The sound on the FLACs is excellent.
For me, these NYP recordings blow away sets or partial ones by Chailly, Boulez, Slatkin (really, please!), Tilson Thomas, Zinman, and Gergiev. (By the way, I do own all of those except the Slatkin.)