Panels
Many of the TV brands have pooled resources, sharing manufacturing costs and often sharing the same panels.
Sony jumped in with Samsung.
LG and Philips have had a long standing partnership on LCD technology.
Hitachi, Panasonic and Toshiba are also working together.
However, it isn't just the panel that makes the TV, it's also the image processing and range of control offered. I had a Samsung LCD TV and it had superb black levels and viewing angles, but it was absolutely impossible to get natural looking colours. Now I have a Toshiba Regza WLT68 and, since I found the right settings, it delivers superb natural pictures, although admittedly the viewing angle isn't quite so good.
The reviews above are a bit odd. If you got your hands on a 103" TV to properly test it, why would you only write a few paragraphs on it. Why aren't inputs and outputs considered and how can you give an award to one when the others are in completely different price brackets and may well be the leaders in their class? Odd.