Behringer Proton

So the two issues first:
* My synth did not come with a US power adapter. I have lots so I plugged it in with the one from my old Neutron...
* It did not power up, so I opened it up and saw that the ribbon cable from the daughter board was completely disconnected from the main board. Simple fix and it started up.

So I am not sure whose fault that is but I was glad I could avoid returning it.
Once it was running, my experience was all positive.

The dual filters is a dream come true, especially paired with dual LFO's and dual looping ASRs. I love the multishape LFO/OSC with morphing control. I don't know why the default is to step them, but once that was set up properly, I am getting so many great complex musical sounds. It even has dual VCA's which offers some interesting ideas for a stereo path (VCA2 is normalled to the output of the VCF2 with VCA1 handling a mix. Simply using them as a stereo pair, you can have two different filters in parallel.

Missing are the excellent bucket brigade delay, sample and hold, and overddrive, but the additions allow for a richer set of sounds than the Neutron, (and I still have those features in my OG neutron... along with a stupid amount of eurorack modules).

I consider an instrument worthwhile if playing it helps creativity and performance. My experience in a few days of use is two new songs based on patches I came up while exploring.

tldr; The synth is great. The quality of the unit including power supply and detached daughter board was disappointing and could create real struggle for a novice.

The best mono module I could find.

I can see why it's more expensive than polyphonic pro-800 - all the patch sockets, buttons and leds cost money. The lights look fantastic in darker room.

The unique feature is double signal chain of separate VCFs, VCAs and LFOs. But some secondary utilities are limited: there is no separate output for noise, no sample&hold, no separate volume control for the oscillators, no effects.

Each oscillator has a "sub-oscillator" which is a configurable oscillator exactly one octave lower, and it can not be turned off completely using device's controls. The knobs can only make them quieter. That was confusing when I watched wave shapes. The external software is necessary to turn them off.

The manufacturer packed too many features into a small box which make it a bit unintuitive. Reading manual is absolutely necessary: the routing and modulation logic is not obvious from front panel, and there are essential hidden key combinations. Thankfully, there is some good guidance on youtube.

For comparison, the 2600 is on another spectrum of design approach: large, easy an self-explanatory interface, more utilities, but has fewer main components.

The hardware quality is perfect, the knobs are solid. The sound is as expected. No regrets, I wish I had more time to explore and experiment.