The Rogue preamps of that era have a really nice full bodied sound, like a warm sweater on a cool fall day. The Athena and Hera were the top of the line back then, and imo were their best offerings by a SIGNIFICANT margin. These preamps use 6H30 and glean its advantages (linearity, detail, speed, bandwidth), but also retain all of that rich full-bodied dynamic sound - and then some!
The Hera II has a LOT of gain, so keep that in mind. It’s not the best match for highly sensitive speakers + amps. Athena and Hera I have more typical gain levels. The gain switch on these units works by cutting signal, NOT noise, so it doesn’t really help the Hera II’s issue. That said if your system matches it, the Hera II is the best of the 3. But even the Athena is still great, and a super value when they come up used. A modern ARC pre like Ref 6 beats it for transparency and clarity, but for the money - damn these give you a lot.
The current Rogue RP-X series preamps have a different sonic character imo. Sometimes I just have to scratch my head lol.