In principle, hardware is well made, although the cable could've been longer.
However, device seems not to be Reaper Friendly....
- the installation is not really as straight forward as one might hope for. At the end I finally got it to work, but I needed a good couple of hours to figure out everything. And even then it worked barely and non 100 % reliably. For example, after starting the Reaper, there was somewhat of a 50/50 chance that the nanoKONTROL would actually work. Also, not sure if it was a must, but it seemed not to be able to work without the KORG KONTROL Editor running in the background.
- after finally getting it to "work" I have experienced a couple of sudden crashes, that are tbh totally for Reaper. Then, on a few occasions, I had to restart the computer because the Reaper would freeze in NOT RESPONDING mode and wouldn't run. The issue was resolved when I "forgot" the nanoKONTROL Studio in the "MIDI devices" and deleted it from "Control Surfaces".
Final verdict
hardware good, buy a longer cable;
radom DAW + nanoKONTROL = maybe;
Reaper + nanoKONTROL = expect problems (Not Responding)