I'm listening to it right now, about halfway through The Carnival of the Animals and I have to say...yeah, it's not something I really expect to listen to repeatedly, if ever again. Make no mistake--this is a Wendy Carlos album. Al is heavily featured but it's a Wendy Carlos album. Which is fine if you like this heavily synthesized sort of stuff but it's not really my cup of tea. It feels like a great soundtrack for a video game but I'm not sure what CBS was thinking when they proposed an album like this.
I'm definitely glad to have it in my collection though. If you're a completist and you can track down a copy for a decent price, go for it. Just make sure you realize you're more purchasing a collectible than a solid musical work.
On the plus side, Al does some neat voices in "Peter in the Wolf" that AFAIK can't be heard anywhere else. So there's at least the novelty of that for hardcore fans.