Well, curiosity got the better of me, so I downloaded it and had a listen yesterday. First, a couple of caveats: the sound is very poor, even by 1948 broadcast standards, and there is significant 'wow' in many spots. Still, there's enough to get a reasonable impression of the performance. The organ and tam-tam are very much audible, actually, but I'm sure I was doing a lot of mental "filling in" throughout while I listened. Part II is sung in English (!), though it's barely intelligible with the poor sound. ("Blicket auf" becomes "Look on high"!) The solo singing is pretty marginal at best, especially from the women, who are just too thin and light (and barely able to come up to pitch). Boult's conducting is urgent and passionate, however, and there are more than a few individual touches that make it distinctive. It's really too bad the sound quality is so sub-par. Overall, I'd say it's not a must-hear, but it still makes for a fascinating listen. It's obviously of historical interest given that it's the earliest known recording (to me, at least) of the M8, and that might make it worthwhile for some. (You can get a taste of it by listening to the sample tracks on the website.)
Russell