Weird choices, right? One one hand, we have a new, mid-range 1080p PJ, and on the other, and older, higher-end 720p...

But, they're both around the same price. - Here's my setup (I have not yet purchased the screen, figured I would wait and decide based on the projector)

Room is ~26' deep
Primary seating is 14' from screen
Second row behind that on a riser (but I'll never be sitting there)
Will be on a 120" screen (16:9) (Will likely be an Elite CineTension2 unit, gain to be determined by the PJ I go with)
My audio section is decent (but not very high-end) stuff, Klipsch Legend speakers and a HSU sub, running either from a Marantz or Onkyo receiver. (Haven't decided yet)

Mounting location for the PJ is still in the air - currently planning a ceiling mount at around 21' from screen, but could mount on a shelf either at 21', or at 26' from screen.

Sources will be 80% DVD / Blu-ray or games, through a PS3. The other 20% being Dish HDTV signals for something like the Daytona 500 or similar.

I guess the crux of the question is - Better quality but older, or newer, higher res?

Part of me says that I can experience something truly high-end with the Marantz, but the other part of me says the Panny will be damn near as good, but offer the advances from 3 years of development.

I've done a good bit of searching, but most comparisons focus on the 720 being cheaper, but this is more of a "For the SAME money, which will I like more?"

So it would appear clear that if the AE3000 is too pricey, I should go with the Marantz, eh?

I don't know if that is necessarily true. There are certainly points from both sides of the argument...I'd be interested to see the results from the panel but here are a few points to consider:
As you pointed out, the Marantz is undoubtedly better build quality than the Panasonic. It will also have a superior lens to the Panasonic which brings its own set of benefits to the table.

Resolution is probably overrated. There are a now famous set of threads on this forum that compare 2 marantz projectors of 720p and 1080p directly...the results tell us that people really have difficulty seeing the difference, even with high resolution content.

LCD has benefitted greatly from 3 years of development - contrast ratio, convergence, features...(and if you were comparing the Marantz to a suitably older LCD, the differences would be more than subtle). However, these remain two very different presentation technologies. Each has its own look. Only you can judge which one you like, so try and get a look at both. If you are having trouble finding an LCD in a showroom (not unexpected), throw a posting up on this forum and see if someone close to your location will invite you over to see one in action. It is my guess that the LCD/DLP difference will be much more substantial to you than inherent advances in techonogy in the LCD itself.

The Panasonic will have lens shift...it sounds like you are doing your own install...don't underestimate the importance of this in your set-up.

I guess the best analogy would be, would you rather own a 3 year old BMW or a new Toyota. The analogy is probably more akin to a 5 or 6 year old BMW with they way that technology changes more quickly in AV relative to cars. Both are different and bring different things to the table. A BMW from 5 years ago is great, and is certainly nicer than a good Toyota today in some ways, but not all. The Toyota has probably closed the gap in many respects and may outperform the BMW in some aspects of driving, but the Toyota will still be a Toyota and the BMW is still a BMW.

So it would appear clear that if the AE3000 is too pricey, I should go with the Marantz, eh?

With your screen size and seating, you'll definitely see screen door from 720P.

AE3000 promices to be a good step from AE2000, so picking it is no brainer.

Do you really want to spend $2K on 720P? Think of it this way: when 12S4 went on sale, a decent 1080P PJ was ~ 20K, so getting a Pana for $2K is a better bargain.

I think your desired screen size rules out the marantz. I had the 12s4 for a couple months and tried projecting onto a 119" draper m2500 2.0 gains screen and it left me wanting more. I came from a da-lite hccv gray screen and the elevated black levels from the draper were unacceptable to me. The projector is suited for smaller screens.

I do agree that you won't find a better built machine then the marantz. I now own an infocus IN82 and the the zoom and focus rings don't have the precise movements that I experienced when adjusting the marantz. I also miss having a quiet projector...I guess that's what you get when trying to cool a 300 watt bulb.

Wait for some reviews on the new crop of 1080p projectors that were just released and go from there.

Thanks for the input, scrubsr1 - I *thought* I had read of people here running the 12S4 at 120", but I would really hate to have a dim image with my 1.8 screen!