It shows how we are all different. I haven't heard the demos on the website but I found the GP500 sound to be superior (to my ears) to the Kawai and Roland.
Yes, that is something that is unfortunately forgotten all too often here on the DP sub forum: That there is no such thing as the one
perfectly realistic acoustic piano sound. And consequently, there's also no such thing as the one
perfect digital reproduction.
Even acoustic pianos have a vast variety of sounds (between different instruments). I bet, that even if you would take one acoustic piano and sampled it into a DP with 100% perfection, so that even the owner of the acoustic piano could not hear any difference, you would get posters here on the forum who would complain that this "perfect" DP sounds fake, digital, toy-ish, not-like-an-acoustic-at-all etc. (you choose one).
Simply because some people would have a different expectation of how an acoustic piano is supposed to sound like, and if the sound that they hear is not like that expectation (in this case because the acoustic from which the hypothetical DP was sampled sounds different), they dismiss it as "not real". Of course, if at the same time they see (or know) that the sound comes from an AP, then they adjust internally and accept the sound as "real", because it obviously is
real, coming from an AP. But the same sound coming from a DP can safely be disregarded as "fake", if you are so inclined, if it doesn't match your expectation.
And then there's of course also the matter of taste. Even with APs, you have people with very differing tastes. One person's dream piano is horrible (sound wise) to some other person. Just now, there's a thread over at the general sub-forum by a person complaining about a Steinway that is gifted to her which she absolutely hates. I guess that for many here, this Steinway would be a dream instrument (especially if given as a gift). For her it is horrible, mostly because she compares it to a Yamaha she used to have which was different...
So yes, I agree, it simply comes down to taste. What sounds (or feels, regarding action) good to one, can be bad to someone else and vice versa, and there is no universal truth which one is right and which is wrong.
For example, to get back on topic, when I tested the GP300 a few weeks ago, I didn't like the action at all (and also totally disliked the feel of the keytops) and didn't think much of the sound either. But then, I've been playing my CA97 for almost a year now. If I had played one of the Casio GPs during that time, I might now be so used to it that maybe I would think that the Kawai feels and sounds strange...