Thanks, koyaan, I'll keep an eye out for it.
Chris
There's a good recording of it on EMI also with Franz Welser-Most conducting.
Anyway, here's my take on the recordings I've known. I own the Shaw version, and wouldn't be surprised if the other Telarc disc with Runnicles mentioned above suffers the same - despite being one of the best recording companies out there, almost anything Telarc records in Atlanta (which means much of Shaw's stuff) suffers from the super-warm, blurry-sounding hall. No detail in the choral parts especially.
I also have a rather different version from the BIS label with Lena Alin conducting. Orff, as an educator, created a version with 2 pianos plus all the same percussion so that smaller performing groups could still play it. I got to perform that version once. Slightly different sound, but it almost makes the percussion stand out even more.
My personal favorite, both for sound and performance, is the Blomstedt version from London/Decca. It did win a Grammy as well. Really good sound, great chorus and orchestra.