Well, I just finished making a track with DSN-12, and I have to say I found it much easier to use than DS-10, which is my only other experience with a synthesizer like this. When I bought KORG DS-10 a few years ago, I spent a lot of time experimenting with making patterns, but I could never really seem to make them coalesce into one song. For me, it really helps that the waveform is displayed visually on the top screen, which makes it easier to understand what is happening when you're turning knobs on the bottom screen. The digital manual is kind of poorly translated, but I found it a little more helpful than DS-10's as well.
The biggest difference for me is the number of patterns you can make though. In DS-10, you have 16 patterns with a maximum of 16 steps each, in DSN-12 you get 64 patterns of up to 64 steps. That makes DSN-12 much easier to use if you're used to (MIDI) sequencers like KORG M01D, because you can sequence an entire song in advance. In DS-10, if you wanted a few variations on a pattern, the pattern bank got crammed full very quickly, unless you edited them on the fly (which I found too complicated). The fact that you only got two synthesizers was also incredibly limiting, having twelve in DSN-12 makes it a lot easier to create layered sounds and harmonies.
So all in all I'm very happy with DSN-12. It improves over DS-10 in every way, as far as I'm concerned. Now what I'd really to see is software that combines this kind of virtual oscillator synthesizer with a wavebank synth like M01D.
Here's the track I made. It's kind of a hodge-podge, but I wanted to try out a lot of different things.