My new Sharp LC-70LE632U was delivered on time this morning by hhgregg. I have spent some time with it going through the calibration steps in the Disney WOW Blu-ray and then watching a variety of sources. Overall I am very impressed with this TV.
Right out of the box in Standard mode the picture was pretty darn good. However, I did notice some motion artifacts around the edges of moving objects, so the first thing I did was turn off the motion "enhancement" modes. These really do make the picture worse, why do TVs even offer these "features?" I then spent some time with the Disney WOW calibration disc and came up with the following settings:
Mode: User
Brightness: +7
Contrast: +29
Sharpness: +2
Tint: -1
Color: 0
Backlight: 5
OPC, Motion enhancement, film mode, etc.: All Off
All other settings are still in their original position. Basically, I reached a point where I am happy and decided not to adjust anything else. The picture quality is really nice. When watching a good-quality Blu-ray, like Up or Avatar, the image is simply gorgeous.
The room in which this TV is placed receives a lot of indirect light during the day (I have huge floor-to-ceiling windows in most of the house), so I might need to adjust these settings a bit at night in a darkened room.
During calibration there are a few pure-white screens and I could see a little bit of dimming in the corners, but it is not really detectable during normal viewing.
A quick note on my setup. I have three HD sources: a Denon blu-ray player, an X-Box 360, and a Samsung cable box from Time Warner. All three are connected via HDMI cables to a Denon AVR-1912 which does all of the video switching and audio amplification for my 5.0 (no sub) B&W speakers. The Denon AVR connects to the TV with an HDMI cable. I think the Denon AVR does some video processing and upscaling because just about every HD channel I tested looked pretty good. (As reported by others, SD on any TV this large is really ugly.)
I haven't turned on the X-Box yet, but I look forward to driving a few laps in Forza 4 later tonight after the kids go to bed.

My two young boys are going to FREAK when they get home and see this beast sitting in the family room!
I have noticed that during calibration with Disney WOW, some of the test bars are not visible on my TV, regardless of how I adjust the settings. For example, when adjusting brightness, there are supposed to be bars for blacker than black, but I cannot see them. When adjusting contrast there are supposed to be bars that are whiter than white (or something like that), but I cannot see them. I think the Denon AVR sees that these areas of the picture are beyond the recommended settings and makes automatic adjustments. Can anyone confirm that?
Just after ordering I was a little worried that 70-inches was going to be too big. My father has the 60-inch Sharp LC-60LE830U and he sits about 15 feet away. I sit 12 feet from the screen, however there was no cause for alarm -- it's the perfect size. And, by the way, I think this 70-inch 3-color TV has a better picture than his 60-inch with the extra yellow pixels. As many here have said before, I don't see a reason to pay extra for the Quattron models.
Overall, I am very, very pleased with this product. A 70-inch back-lit LED smart TV for less than $2k, including sales tax and delivery? That's pretty amazing!