I wouldn't be afraid to buy the refurb, I think there are just some seriously picky people out there. I returned a couple of my pjs when I first got it because I noticed some color uniformity issues, which was only an issue on black and white movies, at least that I could see and the other had a dust blob after I had it a year or so. I think you'll be stuck with it, and won't be able to get a refund, but I think its worth paying 1000 bucks less. I was going to go this route with the 5010, but new pjs will be introduced in a few months, so Im just going to wait. I never noticed some of the other issues that people complain about until I put up a specific screen to see the issue such as pixel alignment, then I was a few problems, but after switching out the pjs because of the other problems mentioned, I still didn't notice the difference with the newer ones. I think some people just want things to be perfect, while others have major problems along with some bad luck. I wouldn't be surprised if its not epsons fault. When UPS dropped my pjs off, they literally dropped them on the porch, that's how I knew they arrived cause I could hear it slam against the porch. I also worked for UPS, and boxes just get thrown around when loading them into the truck. So I can't imagine this is good for the projectors.
whether its a 78% difference, is pretty subjective, my parents couldn't really tell the difference between a low budget 720p projector and higher end 1080p. So I'd have to ask, how happy are you with the picture quality of your Panasonic? do you want 1080p? you could get the 8350 if you don't want 3D. I myself am perfectly content with my Epson 6500 with 75k contrast ratio, but want to upgrade for the 3d alone, so its a pricey endeavor, but I'll pay it to have it. IF you don't want 3d, or higher contrast, why pay the high premium for it, when the cheaper one will do. Is your room light controlled with dark walls? if not the extra contrast might be limited anyway.
Personally I think electronics is pricy for what we get and theres always something newer and better on the horizon, so its definitely better to pay the lowest price point in my opinion. Of course you could wait a few months and see what kind of deals will come to make room for the new pjs that will be coming out