Ok, I just placed an order for 42PX60U with EPP plan. Thanks to this thread.
I was waiting for a long time to buy new 42" Vizio Plasma (for the price), but after reading the reviews by the owners, I wanted to check it out at local Costco. (Also, I read about EPP on Panny, so for me it was a decision time). They did not have 42" on display, but they had 50" sitting between Panasonic and Pio. So it was easy to compare. I have been looking around for a long time and with my experience, Panasonic has the BEST picture in Plasma. The biggest difference I noticed was in the dark scenes. Panasonic shows clear details even in very dark scenes. However, Pio and Vizio (and others in that matter) show only black, washed out, picture with no details. Also, the colors and details on Panny looked very natural (this was on 8th gen panel, so I expect 9th gen will be at least the same if not better). And with just approx 500 price difference through EPP, I think it is worth the price for the quality. So, I placed the order.
I hope I made the right decision. The only advantage with Vizio would have been the return policy.