Just got my PT-AE8000U in and plugged in for a preliminary test. Bear in mind I owned a PT-AE7000U for a year, so this is a comparison as well.
I haven't had a huge chance to play with it yet, but these are some initial impressions.
I'm projecting onto a Seymour Screen Excellence 4K AT 16:9 retractable screen, 100" diagonal, 1.0 gain, 11.5 feet throw.
1.) The unit looks exactly the same as the 7000U. Curiously, though, no manufacturing date on the serial number. I haven't looked too hard, but I found that interesting, since the 7000 tells you when it was manufactured on the side, under the serial number if I recall correctly.
2.) The joystick is still a bloody nightmare, but thankfully you only have to use it briefly.
3.) ECO Lamp mode is EXTREMELY quiet, - I'd say the same as the 7000 from what I recall, but NORMAL-Lamp fan noise definitely seems louder to me, probably due to the increased lumen/heat output.
4.) Brightness is definitely improved over the 7000, considerably so. You still won't be watching 3D movies with the lights on, but you CAN watch 3D movies with a little ambient light (depending on your screen size etc etc)
5.) The high-pitched whine some people are reporting is the EXACT same sound the PT-AE7000U has. I recognized the characteristics immediately (I had the 7000 for a year). If you sit underneath a projector shelf, it will LIKELY not bother you at all. If you sit in front of the projector, with the projector behind/behind+above you - just mounted, it MIGHT bother you depending on your sensitivity to these things. I can imagine most people won't be bothered by it, and some people will be (as this thread proves). I stand by saying that if it does bother you immensely, don't was your time with a replacement because they all do this. Do I think people have grounds to send it back over this noise? Absolutely! But I also think it's not going to bother the majority of people, and I definitely feel bad for those sensitive to it.
6.) The sharpness of my unit is pretty good, though not perfect. My upper right corner is nowhere near as sharp as the center, but still decent enough, especially with some initial tinkering. Will play with this some more later.
I had How To Train Your Dragon 3D Blu-ray on, and it looked great. 3D Motion Remaster was set to on by default. I'd love to say I noticed a huge difference with it on and off in my short test, but I didn't. I'd be interested to see how it behaves with live action movies, and will no doubt update when I get more screen time.
If you guys have any questions, feel free to ask, though I can't guarantee I can answer.