3D Brightness: Epson HC5010 vs. Panasonic PT-AE7000
Not so clear cut here. The Epson has two modes - 3D Cinema and 3D Dynamic. The Panasonic, on the other hand allows you to use your settings for any of the 2D modes - for 3D.
Considering one loses a good 75% of brightness, the Epson really does have an advantage if you want to run 3D based on a 6500K grayscale calibration, you won't have a whole lot to work with with the Epson, and even less with the Panasonic. I've been saying since last year, that if you really want to watch 3D on anything as large as a typical 100" screen, 600 to 800 lumens (2D measurment) s is going to leave you wanting more brightness.
The basic difference then, is that the Epson can do a respectable job with 3D, on under 100" screens, while the Panasonic still comes up short, even on the smaller screens. Neither projector in "best" mode, without a high gain screen, is going to make everyone happy in your home theater or family room, if you choose a large screen, but the Epson has enough extra to do nicely on a 92" screen, where the Panasonic wouldn't be quite that bright on an 82".
In brightest mode, however, using settings Mike came up with for our "tuned" "brightest" modes, the 20+% isn't really very noticeable. I'd have to say both seem about the same. I do know that the Epson is pre-production while I'm not sure about the Panasonic (it was an open unit, but retail product was already shipping.) Pre-production units often measure a bit lower, but let's just say that the Epson, despite the higher lumen claim, didn't seem to be really brighter in 3D. It didn't matter whether I was comparing when using the Epson 3D glasses, the Panasonic 3D glasses, or Sony's "Offical" Playstation 3D glasses. They all appear to perform about the same. Because the Epson projector is pre-production, if previous years are any indication, Epson will want to swap out this one for a full production one, and ask me to remeasure.
Bottom Line on 3D brightness. In a calibrated mode, for those who don't mind the image being what I consider a bit dim, the Epson has a significant advantage, but any advantage in brightest mode is minor, based on my side by side viewing. That minor difference does favor the Epson, but in it's own right, not enough to be a key decision point.