As I mentioned before, I did listen to the second movement, as a download, at some Swiss music site (I forget the name). Sure enough, the 2nd movement starts out at a tempo that is truly slower than normal. This can be verified by making comparisons to a wide number of other M5 recordings. However, I did appreciate the fact that Zinman didn't slow down at all for the second subject (first subject, if you consider the opening material to be just "introductory" material). Many conductors who start the movement REALLY fast, end up slowing down at the next section (or sub-section). This happens on the Danielle Gatti recording, and it happens to lesser extent on the Dudamel one. Obviously, Zinman must have been aware that Mahler doesn't ask for any slowing down of tempo anywhere in that whole opening passage. All of this, then, brings up the question of just exactly what, "with vehemence" means. Without a metronome marking, it could possibly be more of a "mood" marking than an actual tempo request. Still, I agree that Zinman's opening should go a bit quicker than it does. It just needs more oomph.
I did feel that Zinman handled the numerous gear changes in the last seven minutes or so, very well. I could give specific bar numbers, if anybody really wants to dredge all this up. Until such a request is made, I'll just state that I've heard these same gear changes (tempo shifts) handled much more poorly in any number of other recordings. And as for the big tam-tam smash that pretty much negates the brass chorale (which turns out to be a false victory, until it's revived in the finale); the fact is is that it's not clearly audible on a wide swath of other M5 recordings either. Zinman is hardly the first person not to get the most out of the gong right there.
As for the rest of the symphony, I can't comment. Maybe somebody out there might burn me a copy, if they would like to get my two cents about it.