I always lumped Herbert in the same camp as Uberschall, ie massive low end. But upon actual use I found the low end is much more controllable than the Uberschall, it mostly originates from the massive headroom available. Tracks very fast too, which was surprising to me.
When I had an Uberschall I found the low end was mostly in the NFB, it felt like the depth control was fixed on 10 at all times and you can't dial it out, so I didn't keep it for long. The Herbert is sounding more versatile so far.
I have a Synergy VH4 module as well so I'll try that into its power section at some point.
Current stack in our studio at work, from 1w to 180w:
