Agree with you partially on the SD part, as I have only seen the PX80 with that. he PX was very very good, but I was still more than happy to have the kuro. that brings us onto the point of how much people are prepared to spend to get what they want.
It all varies and there is no definitive answer.
Its a never ending game. All TVs have there advantages and disadvantages. But I would be beware of the Kuro as the holy grail of panels, the Unicorn of Plasmas, so to speak. Even if I had an endless wallet I would not buy the 720p Kuro. The new Kuro is going to be a stonker. See above post. But then again its $4000 dollars. So you have to way it up, $4000 for the stonker or half that for IMO something that probably you will be very happy with and which will also blow your socks off!