Two great projectors, similar in many ways, but different in others. It's a tough choice. For those with smaller screens, the Panasonic may well be favored by most, but the larger your screen size, and desire to handle some ambient light for non-movie viewing the more the Epson is likely to be favored. I could live with either of these fine projectors (if only I had a slightly smaller screen), but my personal preference is for the Epson. Still, I imagine I'll be recommending the Panasonic to almost as many folks as I recommend the 6500UB to.
Epson Home Cinema 6500UB vs. JVC DLA-RS1 and RS2, RS10 and RS20
The JVC DLA-RS10 and RS20 haven't arrived yet, but they are similar to the current RS1 and RS2 projectors to give you an idea. The RS1, and the new RS10 are significantly more expensive, with the RS10 expected to sell in the $4000 - $5000 range, so figure about half again as expensive as the Epson. That's a big price difference, and will figure in to many peoples' decisions.
As I frequently mention, I own a DLA-RS1 (current version is the RS1x - which is almost identical, except for some additional color controls). I have run the RS1 side by side with the Epson Home Cinema 6500UB. This is how I see the differences:
The JVC DLA-RS1 has better black levels - JVC is simply the best in this regard. The only projector I've seen that can beat the RS1, is the RS2. As good as the Epson Home Cinema 6500UB is, the JVC is visibly better.
The JVC is also more film like. The Epson isn't quite as bright in best mode, and handles a 110" screen about as well as the JVC handles a 128 inch screen. The lumen difference isn't as much as that size difference, so I'll attribute the remaining difference to those blacker blacks of the JVC. On the other hand, the JVC is only slightly brighter in brightest mode, thus no match for dealing with ambient light. I sure wish my RS1 had the roughly double the lumens of the Epson, when I'm watching sports with some ambient light.
The JVC RS2 is only average in best mode brightness, a step down from the RS1 and well below the Epson. The difference between the RS2 and the Epson in brightest mode is even more significant. All of these JVC projectors, and the Epson, have great placement flexibility. The JVC's have a little less lens shift range, however, that slight difference is not likely to matter for the vast majority of potential owners. The JVC RS1 and RS2 (and we presume the newer models as well) is a natural - very film like, and their color accuracy, extremely good. Sharpness of the Epson 6500UB is a bit better than the JVC RS1 and RS2, both of which are "average" for 1080p projectors. The images below are from side by side viewing. In all cases, the Epson is on the left, the JVC RS1 on the right In all cases, the RS1 is slightly brighter:
That brings us to the RS10 and RS20. The RS10 likely will have a slight improvement over the RS1 in black levels, but don't expect much. The RS20 is the more significant new model, as it should match or beat the RS2 in black levels, but is also reported to be significantly brighter, similar (although perhaps not as bright) to the RS1, and much brighter than the RS2. There are other items relating to the new models that I won't comment on, until I've had a chance to review them (hopefully both over the next four to five weeks).
Overall, I consider the JVC projectors to be superior, but also cost a lot more. The Epson may be my choice if the JVC's were too expensive, but for those not concerned about the price difference, in general, I recommend the JVCs.