I actually received my review unit Primo 8 today! Been listening for about an hour with some brief A/Bing against the Sony XBA-H3.
Firstly, in terms of physical design: I initially found the ear guides very stiff, but I actually quite appreciate it once I realised that once they are bent into proper shape (with some force) they will stay that way. They feel quite secure against the ear in a way that I don't find the floppy / gummy H3 earguides do.
The rest of the earpiece is decently built, but not particularly special for $499. I'm concerned about the use of plastic given that the thinness of the nozzle, but I guess we will see over time.
In terms of sound, I think on first impression I would agree with HeadphoneAddict's impressions. I am a little surprised at how mid-forward these are (maybe coming off listening mostly to the Amperior / H3). They aren't mid forward in terms of mid bass, but something a bit higher in between upper mids and lower bass - something seemingly pretty broad between male and female vocals. I found the silicone eartips are a bit more comfortable and fill in the mid-bass a bit. The comply foam tips seem to make the sound a bit more linear and leaner overall (maybe some more treble extension?), though I would still characterise it as mid forward. They kind of make me think of how my old AD2000 could sound at times. I think I kind of prefer the silicone tip sound.
The whole earphone sounds clean as a whistle. Actually the tonality reminds me of a whistle. There is a certain brassy quality to the sound seemingly due to the mids. Everything sounds extremely cohesive and clean, and though I don't have anything to compare I think this is the cleanest sounding quad armature I've heard except for maybe the UE900. The transients are, like they say on the box, the most surprising aspect of the sound. Lightning fast on the vocals. Crispy clean and crunchy on guitars.
Just compared to the H3, I think I still prefer the H3's bass feel because it feels a little more natural to me in terms of decay. But that IEM is hardly linear. The Primo 8 and the H3 seem like good comparisons since they are quite opposite in terms of signature (U shape vs N shape to my ears).
Overall my first impressions are quite positive. I think vocal lovers will be quite pleased with these.
Here's my unboxing vid!
Edited by a_recording - 6/4/14 at 4:11pm