What music do you listen to and what headphones do you consider better?
I listen to all kinds of music. No really beat heavy music, though. For example, I don't listen to club mix dance music. But I really do listen to wide variety of music. So I'm not a bass head.
Generally, I like a good, emotional, communicative midrange presentation in the systems I listen to. I enjoy good texture in my system, good timbre, a sound that tends to the warm but lucid side, and is wet rather than dry. I also appreciate a rhythmic, tight, tuneful, weighty, and bouncy bass presentation. There doesn't have to an overwhelming amount of bass, just the proper amount and with those qualities. I'd say soundstaging is probably towards the bottom of my list, though I'm always really pleased when I hear phones that do that well.
What phones do I consider better than the S680? Well, as the S680 currently sounds, I say that even the cheaper S400 better. But I do expect the sound of the S680 to improve.
As far as phones in the same price range as the S680? Hmmm.... that's a tough one. Simply because I don't have a lot of phones that retail for the same price.
I would say the Creative Aurvana Live 2! is better, though it has a slightly polite sound. I also think the Audio Technica M50 is better, but it has a certain "thickness" that gets to me after a while. But those phones are almost twice as expensive as the s680.
I also think the UE6000 is a better phone so far. I got the UE6000 for around $75, so those are roughly in the same price range.
The caveat with the UE6000 is that if I don't match it with a copasetic amp and source, it can sound a little less emotional than I prefer. But it can be really good when set up well.
As a frame of reference, I really enjoy the sound of the Audio-Technica ATH-ESW9 wood cup portable headphones a lot. They tend more towards the sound I enjoy. Although those, too, can run about twice as much as the S680 at the cheapest.
You can read about the ATH-ESW9 here:
http://www.head-fi.org/t/524036/audio-technica-ath-esw9-and-ath-esw9a-appreciation-thread