"Anyway, it's a great recording and I'd love to hear Barry's five (or ten or twelve) reasons why something else is definitely better."
It's just that in the mean time, there have been a tremendous number of Mahler symphony recordings released since the latter 70's (or early 80's); and a number of them have superior sound. As good as Abbado's CSO M6 is, I also find it a tad "stiff", for a lack of a better description. For me, the "Alma" theme - the second subject of the first movement - could be a tad sexier; the trio sections of the second movement could have more restless movement - quicker, spin-a-dime changes in rubati (tempo shifts, in other words); the slow movement a tad swifter, overall. All the loud parts are pretty good.
That said, I could live with a tad less brass and more utility percussion at the crests of climactic passages. Philly is better at doing just that. For some reason, the CSO always sound a tad earthbound at the first "Alpine" passage in the slow movement, located about six minutes in. That particular passage is excellent on the Maazel/VPO M6 (and pretty good on the Boulez one too), and serves as my model for that particular spot. Strangely, I found the CSO's "Alpine Symphony" (Strauss) more than a tad earthbound at all the summit passages as well (Barenboim on Erato). Maybe they need to grow a few mountains near Lake Michigan.
As strong and powerful as the CSO play in the two outer movements, I would have liked for Abbado to dig harder with the relentless march rhythms - played by the low strings - at the recapitulation in the first movement (a couple of minutes after the quiet cowbell episode). Gergiev does that fabulously on his new one; and, as I recall, Eschenbach/Philly dig pretty hard there too.
One thing that Abbado does that I really like (and Chailly does it too), is that he takes the final A-minor outburst at the very, very end of the symphony, quite slowly. I really like that!
Trust me, I could easily with this one recorded performance. I'm just bringing up lots of little nit-picky things, because you asked me to. I would, however, like to have it in a DG Originals remastering, as opposed to Galleria. Interpretively speaking, I think I would ideally like Abbado's Chicago M6 for the two outer movements, while using his Berlin remake for the two inner movements. That might really work for me.
I also have Abbado's LFO M6 on DVD, which might be his best overall one.