Please consider this preliminary, but here are my early impressions:
If you think of Haitink giving competent but routine performances, think again. This is vigorous and spirited conducting.
The CSO plays beautifully, and the recorded sound is excellent. I'd say the bass is just a touch muddy, but aside from that, the sound is clear and sounds natural. I wish Orchestra Hall sounded this good when I'm sitting in it.
For those of you obsessed with the tamtam, as I am, it's felt more than heard in the quieter parts. It's clearly audible at the end of the first movement, but it's not the big crash that Mahler called for.
Michelle DeYoung has a bit of a wobble that might bother some listeners.
The set was priced at $20.99 at the Symphony Store, to which the usual 10 percent subscriber discount may be applied.
Cheers!