I've seen the Panny and Epson, but not the Sony, and I own the JVC RS-45. Yes, the Epson is much better, did you guys look in the 3d comparison thread by Zombie in the 3k+ forums.
The Panny has the lowest native contrast, some issues with flickering lamps, and a much dimmer best mode. Hence to get those higher lumens on the Panasonic, you have to crank up the settings and go with a far more inaccurate image than the Sony or Epson.
The only reason to choose the Panasonic is if you are a gamer + need CIH. If not looking for the best 3D image and 2D being the big concern, you'll be hard pressed to beat a JVC RS-45 for movie viewing, but sounds like you guys are more concerned about 3D.
In 2D mode, the Epson has much better blacks than the Panasonic. The Sony hw30 is the best do-it-all projector without CIH, the Epson and JVC have gaming lag. The Sony is going to be a good choice for many.