I used to own a Doepfer Dark Energy (mk1) and currently own a Zoia, so I can try to answer. It’s pretty hard to compare the two as synths. The possibilities of the Zoia are much more vast and endless compared to the DE, which is semi-modular and which contains some pretty barebones modular building blocks when you come down to it. You can recreate the DE signal path and control interface and have a “Dark Energy clone” patch if you want to (actually a good exercise, if anyone wants to rise to it, schematics are here), but it would sound nothing alike due to the discrete circuitry used in the DE and its various quirks. I’m fond of the Dark Energy’s analog-to-the-core, unpredictably messy waveforms, its grit and character, and its musically lovely, squelchy filter. I’ve gotten serious low end, speaker thuddering bass out of it too. Also this absolutely ace feature you don’t see in many other synths: “LM: linear FM (frequency modulation) control to modulate the VCF by the triangle of the VCO in a linear (!) manner”
I don’t think the Zoia is capable of sounding as good if you’re specifically after an uncompromising analog sound, and that should be expected. But I personally would have no reservations making that tradeoff, because the Zoia still sounds PRETTY DAMN GREAT in its own right, has its own character and sound worth exploring, and the Dark Energy can’t do looping, granular, polyphony, advanced logic, complex sequencing (you’d have to buy the Dark Time for that, which is basic compared to the sequencing capabilities of the Zoia), a pedalboard worth of effects you wouldn’t flinch at, controlled or untamed randomness at any point you like, tons of utilities even an owner of a big Eurorack system would be impressed by, etc. In the end it’s no competition in terms of depth, but it depends entirely on whether you value depth or a specific sound quality more.
(Edit: actually, ideally you keep both, and use the CV and MIDI ports to have an analog/digital hybrid beast)
