To me, every symphony Mahler wrote differs from the others.  I think it's
fair to say that he built up a repertoire of musical images, but he comes
up with new ones each time out and finds new contexts for old ones.  I find
that even the marches (to take one obvious example) are fairly distinct in
tone and rhetorical function, from symphony to symphony.

I do believe that one gets a better idea of Mahler's musical imagery in
the songs, mainly because the songs tend to work one image, although as
Deryk points out, vocal music isn't everybody's cup of tea.  I also have
a radical suggestion: The most "typical" Mahler symphony is the 10th,
because he didn't complete it.  The completion is Mahler as heard by
others, and therefore more typical.

Steve Schwartz