The DSM01 is very much the sound I wanted it to be, and it does things that a Moog filter can't do. On other forums, people have compared it to the Pro One filter, but I can't speak to that. What I can say is that it sounds just like a Mopho, and it's great to have that sound back under modular control.
The build quality is good; the knobs aren't as rock-solid as Doepfer modules, but aren't as wiggly as Make Noise modules. The pot shafts are metal, and it's made in San Francisco, like other DSI products. The controls are nicely spaced, and clearly marked. "Clearly marked" is nothing to take for granted, as other eurorack makers try to make their panels as bewildering as possible (I'm looking at you, Make Noise).
Until you start patching stuff up, you don't know how convenient it is to have a VCA built into the filter. That's a very considerate touch, and leaves any other VCAs you have available for other duties. But if you wanted to build a minimal eurorack system, you could get away with the DSM01 as your only VCA, as long as you don't mind your signal always going through the Curtis filter.
The filter is switchable between 24dB and 12dB modes. The 12dB mode sounds good, and will be useful, but note that in 12dB mode, the resonance control does almost nothing. I mean, it does something, but it's confusing. It's not what I'd think of as "resonance." It seems to behave almost like a tiny high-pass filter.
The bottom line is: I'm happy I got it.
A picture of my synth is below. That big, gaping maw there is earmarked for a Triatt mixer, and the DSM03, which will make it complete, at least until I replace the oscillator.