I pulled this prior writeup from when I first tried the VC. I’ll qualify that for the VC I ended up using the Be2 and Auteur pads more than the Universe (all lambskin). That may have been a function of the pairing with a Mogwai SE amp. I would think that the timbre and lifelike presentation of the Auteur generally carry over to the Eikon, which share the same driver. I can’t really speak to tonality other than that the Eikon’s calling card is its sub bass while the Auteur is described as being “ZMF neutral.”
I’d summarize it as follows:
VC: for technical performance, a more energetic presentation, and your system is not overly warm (unless that is your objective)
Eikon: if timbre is a premium, you value sub bass, don’t mind less treble presence, and your system is already warm.
An argument can be made that choosing one may be genre or mood dependent. VC for classical, jazz, instrumental especially strings, and more technical genres. Eikon for rock, acoustic, vocals, electronic, metal, sub bass in particular. Each are versatile.
VC excels in technical performance across the board, with the Eikon having a captivating natural timbre, visceral sub bass, and being more forgiving of poor recordings. VC isn’t metallic or unnatural, but the biocellulose driver realism of the Eikon is noteworthy. VC has additional energy in the treble region.
I’d compare the Eikon to 6.5 inch floorstanding paper cone driver speakers with 2 separate 15 inch subwoofers, and the VC to 5.25 inch floorstanding beryllium driver speakers with 2 separate 12 inch subwoofers: bigger sound vs precision and incisiveness.
Initially, my favorite pads for the VC were the Auteur lambskin - bigger stage and more even frequency response than the Universe, and more sub bass than the Auteur hybrid. However, now I’m leaning toward the Universe lambskin for its increased impact, imaging, energy, and sub bass. It might be due to me being used to the elevated sub bass of the Eikon.
I can see justification for owning each of these, and it is extremely hard to give up the Eikon. It wasn’t a slam dunk.