I think the Colorfly C4 support 24bit-192khz as well? Anyway, there are discussions all over the net about the best compromise being 24bit/96khz, which is likely the best ear can hear.
As for the minor details, breathing of the singer, ambience, etc. all the 3 monster DAP (C4, DX100, 801) can deliver it very well (in fact, Korg MR2 is very strong in this aspect as well). I am guessing if we do a blind test with the 3 DAP, it will be difficult to differentiate which is which.
Anyway, congrats for the wonderful DAP that you have purchase and enjoy it! Really like the quality of the materials used on the DX100, as compared to 801, besides the bigger screen and android UI. I wonder if any users tried to open the DX100 to check if internal batteries could be replaced?