Jason's (Jelt2359) ears are quite similar to mine - I can wear his CIEMs without experiencing discomfort. As such, I've tried his SE 5-way Ultimate on a few occasions.
They offer an airy, massive soundstage that matches my Roxanne with ease. Clarity and detail are also its strong points. The SE 5-way Ultimate sounds remarkably like an open headphone, with excellent spatial and imaging qualities.
However, as a (huge) basshead, the SE 5-way Ultimate lacks in sheer bass presence. Lows are punchy but lean, with texture and quantity falling short compared to say, my Kaiser 10. I listen to a lot of EDM (~2/3s of my music collection), and I've found the SE 5-way Ultimate lacking in overall satisfaction - there's not enough bass to conjure up an all-round head-thumping experience.