Just looked at a PX80 at my local Best Buy. Despite whatever cables and source BB was using, I was very pleased with what I saw. The PX80 exhibits a very deep shade of black. The colors were exciting and realistic. The whites were very bright.
As for comparing displays ... unfortunately, the Kuro was away, about 10 feet horizontally and 6 feet vertically, so no chance at a realistic comparison. From what I could observe, and along the lines of what many people are confirming, the Kuro still had the darker blacks.
What was within comparison range was a 42 Toshiba, LG, and Panasonic 42PZ700U plasma. It was easily discernible to me that the PX80 had darker blacks than all three. It easily beat the Toshiba and LG models and was noticeably better than the 700U. It also exhibited much brighter whites than all three.
That's about as detailed as I am comfortable with being, given my general lack of knowledge in the area of displays and the fact that I have no idea how or if any of the TVs were calibrated and what quality source they were displaying.