I am not sure if we are referring to the same review but I read one (in Chinese) which the person compared the DX100 against C4 (not modded), HM801 (with balanced module) and Sony PCM-D50. The part which he commented that the DX100 didn't sound dynamic enough was when pairing with IE8 and assuming listening when out on the streets. He did a comparison using the following four tracks (WAV, 16/44.1) with JH13 on mid-gain and place them on scale of 5 with 1 lowest and 5 highest. As the comparison is still based on personal preferences, so take it with pinch of salt.
1. Fanfare for the Common Man
HM801 - 3 | C4 - 5 | D50 - 4 | DX100 - 4 (C4 wins by presentation and extension)
2. No Women No Cry
HM801 - 4 | C4 - 3 | D50 - 4 | DX100 - 5 (DX100 wins by perfect, natural reproduction of the singing, sound stage together with refined and smooth mid-range)
3. Trepak - Sonso Handbell Ensemble
HM801 - 3 | C4 - 3 | D50 - 5 | DX100 - 5 (DX100 wins, together with D50, on transparency, especially on producing the clear, light sound of the handbell)
4. N'Kosi Sikelel'l Afrika
HM801 - 3 | C4 - 4 | D50 - 4 | DX100 - 5 (DX100 wins by excellent mid-range density (not sure if using the right word) and layering)
His verdict is that DX100 has a very neutral sound signature but does not mean unfeeling or cold. It is smooth, natural and does not color the sound. Weakness is that, for him, mid-range doesn't sound dense enough when listening to male vocal. Bass and mid-bass can use a little more weight and impact.