A fun little groovebox that is best when you have some alone time with your headphones. But I doubt its usefulness in a long term, or the ability to 'grow up with the user'.
The interface looks very cool, but as others already mentioned, knobs are wobbly. Most of them are also very thin, and very tightly packed, which is not great in terms of overall control, if you have bigger hands. That gets even more tiresome as the hours go by.
The portability is also questionable, because this thing needs many batteries and burns through them fast. It's probably due to the internal speaker, which is poor quality and has no low end. In my opinion, it's just bad design.
I know there are people that can link several of these boxes and make live music with them, but the amount of batteries (or Korg-specific AC adapters) required is ridiculous, an exact opposite of "eco friendly". It might look flashy on Youtube, but IMO it would be wiser just to save up and buy one decent synth.