Well. I just got my new 5084 in the mail today after taking the plunge. I did quite a bit of reading on the forum, even went out and bought a Panny 700U, brought it home and tried it. I figured the best way to really determine picture quality was to hook up the old PC and play some straight HD from my computer that was recorded, full 1080P, for a video I am making.
The Samsung has a really, really nice picture. The color levels are a bit hot, the blacks are very very good and the bezel looks stunning. I had the two TV's right next to one another each receiving a feed of the same video. I did not notice any "blocking" as was mentioned in the prior post even when I was inches away.
It was my opinion that the Panny was a bit to dark for my liking. The Sammy seemed to have a bit more life in it.
After hooking it up to good old SD analog cable I browsed through the channels abit was decently pleased by the PQ. I'm not saying that it super, I'm saying it was watchable. I had ESPN and CNN on for at least 15 minutes each and did not notice any jitter issues. The picture I was looking at was not blurry, just a bit blocky due to the poor signal. I am upgrading from a rear projection 42" and the picture looked better than before so I'm presuming the newer processor cleaned up the image a bit.
Later this evening I will hook up the old DVD player and see how it works out.