Oh, I really love this one! I'm a big fan of how that little theme prefigured in the accompaniment of the first section of the exposition of the first movement keeps coming back in various guises, transforming before the listener's ear slowly but surely before finally entering in all its glory at the gorgeous passage with piano and strings. One of the very best uses of cyclic form, in my eyes.
And given Saint-Saens' little experiments earlier to adopt some kind of cyclic treatment of melodies, most notably in the Piano Concerto n. 4, I feel the self-declared "magnum opus" title really does apply here pretty well. I've listened to all the concertos and the trios and the quintets, (some of) the operas, the Christmas oratorio, the Requiem mass... and there is something here which just feels a little bit better expressed. I have no real substantiation for this feeling, just the feeling itself.
I really like Munch and Barenboim, but there are so many other lovely recordings out there. There are also a lot of rough ones too, though, so it takes some sifting to make sure you've not stumbled anywhere too far afield.
What Dvorak's 7th is to the Czech music scene (that sort of first big-deal internationally acclaimed blockbuster symphony), I feel like Saint-Saens 3 (without casting aspersions on d'Indy or Bizet) is to the French. Of course Berlioz wrote a few corkers, but that was fifty years prior. That Franck and Chausson wrote theirs so soon afterwards is particularly interesting to me. I like those two as well, and feel like they are a sort of natural continuation for listeners who enjoy the Saint-Saens.