if money is not taken into account, will you choose very good condition, high end kawai mdls made in 1990s such as us9x, ku80, xo8, us95, over current kawai mdl K6?

nowadays pianos are produced as a batch in a product line, whenas pianos were not as common and were made with very good quality materials in 1990s. And kawai in 1980-1990 have the best sound. More round and mellow.

So i am not sure other than the age advantage including warranty and the 3nd generation Kawai new action, are there any other advantages to buy a new K6 over second hand high end models maybe 10-20 yrs old?

New models have the Millenium action, which I feel is a big improvement.

I have a 1990 us6x and I can say the action is incredible. I haven't played the millennium 3
but I can say that the action is made of the abs/styran, so it's not a wood action but not the same as the millennium action. In fact the only wood I can see is the hammer shanks. I have also been told that the 90's models were made with better materials. I don't know for sure if that's true but I can say my tuner tells me this is the nicest upright he services, and he services a lot of pianos.

For me it would all come down to condition. My us6x was in like new condition when I bought it a year ago. I paid 5 thousand for it and it feels like a great value to me considering the condition and how much I am in love with this piano.

bfeils found one in like-new condition... that's the type of use goods I would buy.

A new K6 doesn't just have new technology but also new strings, hammers, keytops etc.

I haven't heard of any evidence pointing to higher quality in the 80s and 90s vs. today.

u are so lucky to get it for 5k, are you talking about us dollars?

Yep. US dollars.

Well, you should get what you like.

You ask, "...if money is not taken into account, will you choose very good condition, high end kawai mdls made in 1990s..."

...and to that, I will say, "No, I would get a new EX, RX, or Shigeru in the longest size they have." And on second thought, I think I'd like to comparison shop among the other fine piano makes of the world before I make up my mind, though I would weep no tears if I ended up with an up-model Kawai.

As far as satisfactory used uprights go, I would say, "Fine, as long as they are inspected by a qualified tech, hired, paid for, and reporting to you alone." Which you do not mention. This is the advice for anyone buying a used piano. The modest expense of an inspection can save you an ocean of tears.

I don't know how to evaluate your assertion than Kawai models of the 1990s are superior to those of today, and were made of better materials. There is room for doubt, for the model lines have gotten noticeably better-playing and -sounding, including several iterations of the Millennium action, which is wonderful. Kawai's R&D has not been standing still over the last 22 years. However, global deforestation is a fact of life for makers of all wood musical instruments; old-growth spruce has been substantially consumed; they are all having to do more, with both less, and not-as-good. It is a subject that is big enough that it will not be discussed in a single paragraph, and--- whoops--- there mine goes.

Anyway. Get what you like, and be happy.