These were announced last year, but they're finally becoming available.
In some ways, similar to Axoloti (STM32F4 + DAC). It's user programmable (for programmers, anyway), but comes fully set up as a digital monosynth with FX.
Oscillators created for NTS-1 will run on Prologue and Minilogue.
I couldn't resist, mine should arrive on Friday.
I have a Prologue 8 and I'm using a lot of oscillators and effects that other people did.
I'm a newbie into coding, I've tried several times to set the SDK, libraries, github desktop, make, etc and can't get to compile anything...
Creating oscillators and FX for the NTS-1 is certainly not as musician-friendly as using the Axoloti patcher to create patches.
Also, unlike Axoloti, the Korg logue SDK only opens up writing oscillators and FX. The rest of the firmware isn't open.
I installed SDK before ordering the gadget.
Update: I just sold it on Reverb. I used it enough to satisfy my curiosity and form an opinion.
The good: it is nice looking, and sounds good.
The bad? It's sold as a product, but it's only a cheap development system for REAL Korg synths. For most users, a toy with very limited capabilities.
I love my NTS1. It’s a very capable mono synth with a decent arpeggiator, although the arpeggiator controls require a bit of cumbersome diving. Set the arpeggiator to octaves and you can make some surprisingly awesome bass lines with that little ribbon keyboard it has. Plug in an external keyboard and the arpeggiator becomes very useful.
Mine also arrived this week. Played with the SDK before, everything works well. Now to get to know it and actually try coding something useful 
Plan is mostly to use it as an effects-box, but now I have to get a bunch of converter plugs. Also a bit annoying that the output is on the front whereas all the other plugs are in the back.
