Okay, I just wanted to give my initial impressions here before I add to a bigger review pool...
This is the first 'universal custom' type earphone I've tried, and honestly I do not like the form factor. The nozzle size just seems a bit too wide for long term comfort for my ears - my ear canal starts getting sore within 15 minutes of wearing them. The weight distribution of the large body and the weight of the 'audiophile' cables means that that they don't feel entirely secure when moving around.
In terms of technicalities, the IEM is quite impressive, with a tremendous feeling of speed, resolution and detail. Everything sounds lightning fast, with fantastic extension on both ends - especially on the low end. Everything sounds clean and coherent.
That said, I don't really like the tuning, which is extremely V-shaped and lean. It's clear that the dynamic driver has given the earphone massive sub-bass extension, but it seems poorly integrated with the rest of the signature. The sub-bass really kicks but because there is no accompanying mid-bass warmth that blends it in. It's a fun effect if you like your sub-bass but seems fairly unnatural, as if someone had applied a high quality 'super bass' EQ.
The highs are also very brittle and seemingly metallic in quality, though I don't find them tremendously sibilant - just overemphasised and again poorly integrated into the signature as a whole.
These have the kind of signature that makes it possible to pick apart the music really well (I like them with densely layered synthesised instruments), but I don't find myself really relaxing and connecting with the music with these - there are too many elements that not too subtly call attention to themselves.
Of course I am speaking from the perspective of expecting to really love something for $650. These are easily on the same level technically as any $200-$400 IEM that I have tried. Because of both the ergonomics and signature of this IEM I would not pay $650 for them, though they make for an interesting listen.