I purchased the Samsung 75 in. about 2 months ago. All I can tell you is, I have never had a second of regret.
I have looked closely at the Sharp 80in you referenced, and IMO there is no comparison. The Sharp picture looked "soft" in comparison to the Samsung and the contrast ratio was visually poorer. I know that Samsung has had problems in past years with clouding and flashlighting around the perimeter of the screen, but the ES9000 75in has never exhibited any of this. At all. The color of the Samsung appears more natural and lifelike to me than the Sharp as well.
Nobody could claim the ES9000 is inexpensive, or maybe even a bargain. But, that is in the eye of the beholder is it not? When you get up into the larger screen sizes, it seems that it becomes progressively more difficult to manufacture a set that avoids the traditional pitfalls such as flashlighting, clouding, uniformity, color accuracy, etc. Having lived with the ES9000 now for 2 months, I can say unequivocally that to my eyes, it does an excellent job of avoiding these shortcomings. I find that particularly impressive considering the fact that the set has such a thin bezel, which I find attractive.
Having said all this, I don't think I could call the Samsung a bargain. 9k is a lot to spend on a television. But for those who have the funds, I believe the ES9000 delivers one of the best, if not THE best picture in the 75 in. category.
Others are free to disagree.