All three had good scores. I think Elfman's scores were a little more complex and "epic," with more of a mature undertone grounding it and Young's was a little more cartoony and light, but both were good. I will give Young credit for the Sandman theme (which he uses in variation during the flashbacks and the great birth scene), the church scene which combined the spidey theme with his dramatic symbiote theme and the use of Elfman's themes when Harry shows up at the end of SM3. I also really liked the music he used when Harry Osborn died.
I think overall I'd be really interested to see what Elfman would have come up with in SM3, but I'm happy with Young's work that created some fine music in crucial scenes. And while not iconic like many fans hoped, Elfman's score and themes for the first two movies are very poignant and unique that give them their own little epic-ness.
Vis is going to hate that last comment.