Re: Fill factor. I have truly no clue, but I would think that the fill factor would remain the same, unless sony adds MLA on the panel. (I say this with the belief that I highly doubt they re-engineered a new panel for this machine).
I figure they have done something with the optics to reduce black level, and by virtue of increased brightness the contrast ratio would go up. In fact, that contrast ration increase is believable, but not the reduction in black level, which would have to be seen to be believed.
Sharp xv-s55u (Don't laugh) :)