I have mine for a couple of weeks now (old design) and I like it. I love the slightly toylike look. There are several good reasons to change the design (tripbeat claimed it´s to crowded in the box), but the old design is just cool.
Sound is also quite nice. It is not the instant Moog-Bliss sound, but I think the dual filter really provides tons of interesting sounds. I think I slightly prefer running the filters in parallel, but variable bandpasses, lowpass with a notch or just spaced lowpasses also are fun. Independend Resonance controll would be nice...
I am quite happy, that the ADSR is not wired to the VCA. For many standard lead and sequencer sounds a release is not that important and you have full independent Filter control.
The oneshot mode for the LFOs is brilliant. In many cases you get by without additional Envelopes.
I got it after playing with a Dark Energy (1) and the Microzwerg. Dark Energy has the more "round" sound out of the box, but I had way more fun with the Microzwerg.
I guess in the long run it will mainly do high pitched stuff (where digital dies due to aliasing), stuff with fast modulation and the cool Filter-Split sounds. Also great for layering with some other sources.
Probably will add a passive attenuator and multiple in the long run.
I think in terms of flexibility (and for some sounds) it can easily hold it´s own against the other "low end" stuff (Minibrute, Dark Energy, Mopho, Evolver).
The DE is more instant gratification, the Mopho and Evolver have more Modulators (especially Envelopes). But: The Zwerg has way cooler Filters (my opinion).
Not a huge fan of PWM and Sync on the Microzwerg, FM works great (even if an attenuator would have been nice).
Of course it can not really keep up with the big guys. A modular designed around Cwejman, Intellijel or similar brands will be more powerful and flexible. On the other hand it will be at least 3 times as expansive and not available in such a tiny form factor.
About the knob ranges:
e.g. it is nice to be able to detune the 2nd Osc by an additional Octave, thereby reaching 2´ and 64´, but it also means, that dialing in a specific beating of the oscillators is tricky to say the least.
Similar arguments are possible for the modulation attenuators (especially contour tends to stay at the lowest 20% for most sounds).
Overall: Very nice box. Not necessarily the instant monster baseline machine, but can really add to your sonic repertoire.