The Russian guy (I’m Russian too) wrote on YouTube practically the same that I was going to write here, although I never played these new keyboards. The WK-3800 and CTK-900 were in some way unique and pretty good for their prices, so people expected the next generation of keyboards to be even better.

But all new CASIO keyboards are equipped with AHL sound engine that (some) people consider as much less impressing than ZPI one.

So this man who played these new keyboards at exhibition in Moscow concluded that among present CASIO keyboards only CDP-100 and CDP-200 are competitive due to their low price.