It's certainly has to be one of his most 'idiomatic' (M6). I love it as well, and have actually had a long history of both hearing it, and performing in concerts of it.
I think it's the start of a 'political trilogy': M6 - M8. It's simultaneously his most 'German' (Brucknerian) and anti-German symphony at the same time. It's a sort of an Austo-German 'Rite of Spring' before Stravinsky's "Le Sacre". In fact, if you combine the mountainous 'walls of sound' from the finale, with the alternating mixed meters from the trio sections located within the scherzo (Alma's thought of her children playing games and ziz-zagging in the sand in arrhythmic patterns) , you get - voila! - the Rite of Spring. Strange that it had its premiere in Essen, of all places, because you really could watch news reels of the troops charging back and forth on the western front while listening to the fast sections of the finale, and find that those two seemingly incongruous things fit perfectly.
