There's no question that Morton Feldman's music can be maddeningly long, minimal, and soporiphic to those unwilling to enter his particular sound world. But if you're willing to try, this is as good a recording of his music as you're likely to find.
As far as the composition, I personally found this to be as strong a work as he wrote in his later years. And as for the performance: Kronos has never sounded better. This work requires stamina, focus, and coloration as opposed to dexterous virtuosity (of which they were certainly capable); Kronos does the job magnificently. Kudos to the recording engineers as well, who manage to emphasize the "sound." Aki Takahashi was one of three pianists of choice for Feldman during his lifetime, and I can hear why.
The performance is maximum length for one CD (79 & 1/2 minutes) so I suspect all parties involved wanted to see that the work was SLOW enough, but fit the format's constraints.
If I was to recommend an introductory recording to Feldman's music, I'd probably choose "Rothko Chapel" first. But if you really want to dive in...try this one.