There"s always a trade off. It"s a shame they can"t get their hands on a quality semi-weight synth action at the $1999 price point. Or maybe it was more important for them to get under 20lbs. It"s an otherwise killer board.
Can you copy/paste their review? It"s blocked for me due to expired certificate.
I think this is the relevant part (translated with Google):
"....The touch behavior, on the other hand, is somehow strangely 'flubbery' - forgive me for the rather non-technical attribute at this point, but it actually best describes the fact that the keys have a - felt - exponential rebound behavior: Very soft in the first third of the way back , then powerful and in the last third softer again. So you always have a kind of trampoline effect under your fingers, which is quite fun with Rhodes and Clavinet sounds, but works poorly with expressive piano playing. In addition, the keyboard frame in the device apparently tends toto swing up when playing vigorously, which leads to an audible tonal resonance. For a while, it was obviously not well advised to deviate from the previous manufacturer Fatar and to build in a Young Chang in-house development...."