I can't say that I have experience of either, but I do own a pair of Shure E4c earbuds, which I picked up for a bargain $199 about a year ago. From the reviews, I suspect the SE310s are very similar, in which case don't hesitate. The sound quality of my Shures is superb - natural with no artificial extras (very important as I listen to classical music). What's even better is that they isolate outside sounds extremely efficiently. I use these on flights and when outside and they work hugely better than the Sennheiser noise-cancelling earphones I had before.
I'm planning on getting a new pair of headphones as my V-mode Vibe just got broken, and I'm considering a really good pair this time.. I have 2 choices for now, a $250 Shure SE310 earbuds or a $120 Sony V700DJ.
I won't be using this as my main headphones, I have a bluetooth headset (which doesn't compare to my Vibe) connected to my phone for regular walk to college (simply 10 mins). This new one I would use for long trips or long waits, especially on plane trips, so I don't mind the big size of the Sony 'phones.
So which one would have really good sound considering one is smaller but more expensive, while the other is bigger but cheaper?

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