This is a very interesting CD. In purely technical terms, however, I could agree on virtually everything stated in the previous review below. But I take a different stand in how to evaluate Bruno Maderna's interpretation of the Mahler ninth.
A bad interpretation of the Mahler ninth would be an interpretation that misses Mahler's points. Bruno Walter's 1938 performance is not a bad interpretation, despite the all the technical flaws. So what is a good interpretation? Leonard Bernstein has argued that an interpretation of Mahler cannot be exaggerated. In Bernstein's terms, this means apparently that every instruction in the score should be inflated as much as (reasonably) possible. I suppose that many Mahlerians share that view. But in Bernstein's case, this view has led him to add notes that are absent from the score, such as a bass drum blow at the end of the finale in the first symphony (DG), generally grossly exaggerated phrasings, a "Ligeti-like" conception of the funeral march in the Berlin ninth (DG), etc. By slight contrast, however, I would say that an interpretation of Mahler should emphasize the structural effects of his symphonies. But in my view this does not mean that notes should be added and that phrasings ought to be heavily mannered, as if Mahler's works were orchestral showpieces (like Tchaikowsky's "1812"); only that the structural line and its climaxes should be emphasized. After all, Mahler was not composing understatements, but profound, revolutionary, and outstanding music.
So, in Maderna's performance we are not facing a bad interpretation. It is extraordinarily intense. The performance is not an understatement but a carefully planned and emotional interpretation. The climaxes come off with a tremendous force and tortured tension while the structural line and logic of the work is maintained. As is pointed out by the previous reviewer, what is most striking with Maderna's interpretation are the deliberate - or indeed "exaggerated" (!) - tempi choices. This is especially the case in the first and fourth movements. But unlike the other reviewer, I don't see this as a flaw. It contributes to make it to a very memorable account - that is, a good interpretation.
In addition, BBC symphony orchestra responds very well to the conductor's view. The recorded sound is a good, live stereo analogue in a fine remastering. (Unfortunately one can also identify one persistent cougher throughout the whole work - why didn't this man leave the concert?)
To summarize, then: this is a very interesting, illuminating but alternative interpretation, which one wants to return to many times. It is never dull but full of excitement. For reference, one could consider such seminal (but more or less technically flawed) interpretations as Klemperer (EMI), Walter (EMI), and Horenstein (BBC). However, I don't think that Maderna's interpretation should be anyone's first or only CD with Mahler's ninth. But if you appreciate those performances just mentioned, or even if you like Bernstein's Berlin Mahler ninth (DG), which also is technically flawed and shows different sorts of exaggerations than here, this is also a valuable CD for your collection.