I hesitate to recommend this as the top choice for anyone looking for their first Mahler 9. If you have not heard the Ninth at all before, this recording by Walter is not the one for you. Barbirolli's and Haitink's (with Amsterdam) Ninth combines good sound with excellent playing. And Karajan's ninth with the BPO is also a good place to start, although there are those who argue that Karajan did not produce the Mahlerian sound with the BPO.
For those who already have a Mahler 9 and wish to supplement their already valuable collection with historical recordings and alternative interpretations, well, what are you waiting for? Grab this CD. You can go no more historical than this. This was Walter's last performance with the VPO before he fled Austria to escape the Nazis. One hears in the music the tension of those last remaining days before the war, or so I imgaine.
The playing of the orchestras might draw different opinions from critics, the sound is admittedly of low quality ( though in view of the date - 1938, the engineers in charge of the remastering must have done wonders), but mix them all together, and the result is potent electrifying music! Listen to the first movement and feel your goose pimples rise, for this was what it did to me on the first listening, and still does.
Get this, in this remastering or any other. It is worth your while.