You're really not going to get a fair consensus on this issue. Sound quality is incredibly subjective, and it actually varies depending on the user. For instance, I sound perfect on a D2, but my sister is a bit hollow. And neither of us sound good on a DInc, but my cousin sounds awesome (same DInc).
No idea if it's the vagueries of noise cancellation, the shapes of our heads in comparison to the phone shape, the modulation of our voices compared to the sensitivity of the mic... No idea.
The only way to really know is to really test it for yourself. If you get it in store, you get 30 days to change your mind and pick up the other one, or cancel your contract altogether. But if you're asking my opinion, for me, the D2 is better than the DInc.