Just got my Panasonic PT-AE 8000u.
After evaluating for about 4 hours, I absolutely loved my experience with the Panasonic and I'm keeping it.
I definitely got pretty lucky from what I can tell on the quality of my Panasonic as everything seems pretty much flawless. Convergence, focus uniformity, color, uniformity, sharpness, etc all look excellent on my product.
As far as as a comparison to my old previous HC3800 it's easy to make. Everything is significantly better. First off I immediately notice the much brighter image. According to projector central reviews, the HC3800 is about 1000 lumens in the bright accurate mode, and the accurate Cinema 2 mode on the Panasonic is around 1600 lumens.
Next, the black levels were immediately noticeable as considerably better. I have had the Iris enables on the Panasonic now these 2 days and I haven't heard it make sound or anything and don't ever really notice it moving. I can tell it does work though when I change what I am looking at on my computer as my source is an HTPC. So when I launch a video into full screen for example I can see the progress bar get lighter and darker and stuff. Blacks are so dark compared to what I was used to on my HC3800 and the image pops considerably with the much higher brightness than I'm used to. Shadow detail in movies like The Hobbit and Harry Potter really impressed me as well. Overall it so much more closely resembles how I remember The Hobbit looking in the Theater.
None of this should be a surprise though as the Panasonic was significantly more expensive than the HC3800 at any point.
The other main thing i spent a lot of time checking during my evaluation was 3D. My only other 3D display is my computer monitor, it's a 120Hz 2nd generation 3D vision display with LightBoost tech and such. I have seen lots of 3D at the store and I was at CES just last January as well.
Well, I can say the 3D from the Panasonic thoroughly pleased me. I was able to set the Panasonic to Dynamic mode with some slight tweaks to the color contrasts and it produces an extremely bright (~2400 lumens) picture with reasonably accurate color. Nothing that screams green or blue in the color to me, especially with the glasses on. Coupled with that I was able to set my Panasonic third generation glasses to the "Light" mode and I went ghost hunting. I was able to see some crosstalk in the reference scenes that most people here talk about (space ticket in Despicable Me) but over all the crosstalk was very minimal in my opinion and far from distracting. In the vast majority of films I never saw any crosstalk, especially when I wasn't actively hunting for it. I sampled long scenes from Avatar, the Avengers, Harry Potter, Toy Story 3, Despicable Me, and The Hobbit. After all that I only saw a handful of ghosts and they were pretty slight and again IMO not distracting to me. I also played some Guild Wars 2 and Team Fortress 2 in nVidia 3DTV Play and saw no ghosting in TF2 and only a small bit in GW2, but not enough to cause me any problems or distract me from the awesome immersive 3D game play.
I'll leave you with a few pics I took of my screen so you can see the quality of the product I "lucked out" on.
The red seems a bit off to the side, but this was taken on the edge of my screen. In the middle the red is aligned perfectly and on the other side its off by that 1/2 pixel or so in the other direction, so it's very uniform overall.