"Stenz, Nott, Zinman, or Jarvi"
These are all lower level recordings than Bernstein/NYPO or MTT/LSO. They are all really worthy, so do give them another try by turning up the volume more than you're used to. Stenz has the best finale ever (in my opinion). Nott's is a 'darker' performance than Stenz, but has the mandolin, guitar, cowbells and deep bells captured with such beautiful clarity. He also has a rockin' finale. Jarvi is agruably too fast in the first four movements - treating them all as a single prelude to the finale. But the finale is very good, so just listen to that movement.
Zinman is the lowest level recording of the four, so it really needs an extra boost on the volue knob. But it's also quite worthy. The central 'moonlit' episode in the first movement is the best I've ever heard it, and with truly gorgeous harp glissandos. He also has an excellent fourth movement (2nd Nacthtmusik). I just listened to the Zinman M3 earlier today on my Bose 'thingee' - turned way up - and it's really quite excellent. Birgit Remmart sounds great. My favorite M3 remains Honeck/PSO, but I own whole bunch that I really like almost as much.
And thanks, guys, you've convinced me not to spend the money to get Gielen/BPO. I'm sure it's quite good, but I'll stick with what I already have. By the way, the 'remastered' Boulez M7 from the complete box sounds very good now too.