DDMs highs are slightly recessed. I think rawrster's review has got it just right about the treble of DDM (he's a self confessed "treble-head" though
). If you are coming from RE0, DDMs will be found wanting in that department. As I mentioned in one of my quick notes, for treble - RE0 > PFE > DDM. Yet, there are things that DDM does which no other IEM of mine does in the bass and the mids.
In terms of build quality, the Zirconium Panas are far better than the Cadbury Gems err... the DDMs, I mean. Besides, the Panas have a detachable cable and you can substitute a Sleek Audio cable easily for it - a luxury at the $80-90 price range. But, their filters do fall out easily. DDM has an odd shape. I don't have an issue with fit, some people do.
Panas cables are shorter in length - only 1 m. Radius has a nylon cable that does not strike as great. But, rawrster mentioned that these are better than e-Q7 cables and less microphonic too. Keeping in mind that DDM was targeted at this segment, it makes sense why they have a nylon, microphonic cable.
I guess in terms of isolation, Panas will be better than DDM.
HJE-900 are slightly "living on the edge" in the highs, though they are said to be better than Hippo VB in that aspect. A foam mod or a proper tip is a good solution to this. DDM kind of treble won't even step into sibilant land. You have to pay a bit more attention to the highs to know that DDMs do not "focus" on it, but it is not that terrible after all.
Both Panas and DDM are said to do certain "special" things with Mids. Panas are probably a bit more warmer in the mids. As far as I've heard, DDMs are very 'musical'.
HJE-900 focuses on Mid-bass mostly. I am sure it has much more mid-bass than the DDM. DDMs do sub-bass too, do not know much about Pana's sub-bass capabilities. I don't know if Panas "rumble" like the DDMs do.
Pana's sound stage has more depth than width, IIRC. DDM's expands and contracts with the recording. It can be very wide sometimes to feel an "out of ear" sound, yet terribly claustrophobic in a few passages.
In terms of sound signature, all I can say is DDMs are unique. If you don't get used to the signature, you are going to hate it completely. There are moments where you stop to think "It doesn't sound like this with my other IEMs, headphones, speakers...."... only to get lost again in music. Panas I suppose have a bit of analytical character too.
I would not say A is necessarily better than B here. It's a choice - I went for the DDMs as I wanted something totally different from my usual PFE/RE-0 signature and I am happy that I got it without spending a fortune. You may not go wrong with either. Just be sure to read many reviews on head-fi before picking one.
