RN6, CP-100+ and now with OC Studio Frozen 8w (new release). Richer, fuller soundstage (that's already pretty wide). Added a bit of depth. Bass even tighter and notes are more defined/outlined. Felt like there's an increase in bass quantity, but never bloated. The mids are the highlights. Brought out what's slightly missing with the RN6, which in effect created more layers and separations. Wonderful combo! This is with the default Red filter and DX320. Running through A100TB+PS100Pro is yet another experience. Other $4-5K+ IEMs may be technically better, but I'm not sure can provide the same level of engagement.
Have a new cable coming too, so excited and will update with impressions on the RN6. Totally agree, there are more technical iems at this price point, but RN6 still offers very high levels of separation and detail retrieval, really nice sense of space, and a tuning that's engaging, clean, warm-neutral and enjoyable across a wide range of genres. Excellent timbre too. That plus really best in class bass (imo), and fantastic comfort makes them my favorite EDC that I've tried to date.