I didn't read this whole thread since it is long, but I may be the perfect person to answer the original question.
Get the S2.
I have the Panasonic 65 V10 and it is an excellent TV. With calibration the S2 should have a similar picture.
I upgraded from a 60" Sony 60A3000 SXRD that I gave to work. ( i own the company)
I also bought a Mistu 65" 737 model DLP for my parents recently. It lacks the auto-iris.
Upon changing from the SXRD to the Panasonic, I wasn't blown away. It was a substantial improvement, but I was expecting to be blown away by how awesome the picture was. I wasn't and initially wondered if it was worth the $ I paid ($3600). I think this was just that I had amped up expectations and how good the SXRD was. But, now I go back and view the SXRD and it disappoints me. I've become accustomed to the better picture quality and it hurts a lot going back to anything else. I now notice the silk screen effect, average black levels, and bad viewing angles on the SXRD more than I ever did when it was my primary TV.
The Mitsu DLP sucks compared to either the Sony or the Panasonic. It isn't even a contest and you WILL NOT be happy with it. It's fine for my parents and I can watch it and it looks fine in a lit room, but it isn't a great TV. It's an adequate TV and the saving grace is the $1000 price tag. Colors are off ( i never calibrated it beyond setting cinema mode), silk screen effect, poor viewing angles, poor black levels, and poor uniformity.
