Listened to the Campfire Audio Holocene today, and I think I am ready to share some first impressions.
The Holocene has a triple-BA setup, and the shell design is similar to the Andromeda.
Ironically, the shell design isn't the only common factor between them.
The Holocene seems like a cut-down version of the Andromeda (to be more specific: Andromeda S). It's a bit brighter than the original Andromeda due to more mid-treble emphasis but other than that the atmospheric nature of the vocals, the wide staging and great imaging reminds me of the Andros. These do have a bit more pronounced bass response but other than that, in terms of technicalities, it's quite close to the Andros. The bass has a nice rhythm to it and doesn't sound as anemic as many other BA offerings.
As for sources, I personally liked the pairing with the Sony WM1A a lot, and despite the low ohm nature, it didn't hiss at all (unless you push the volume very high with no music playing). The Lotoo PAW 6000 was the most revealing in terms of pairing but it further pronounced the treble emphasis on some tracks.
The Holocene has become my most favorite of the 4 new Campfire Audio IEMs. It's also priced the highest, but for my tastes I'd pick the Holocene over the Mammoth almost always.
Great impressions. Look like the Holocene will be right up the alley for many who roll down at that speed.