Officially the RS2 is not as bright as the older RS1. The RS1 claimed 700 lumens (we measured 763 lumens in best mode and upper 800's in brightest).
The DLA-RS2 is not as bright as the RS1, but it's higher contrast seems to make up for that a bit. JVC rates the DLA-RS2 at 600 lumens (at D65).
In Cinema mode, lamp on full power, the RS2 measured (with the zoom lens in the middle of its range) 537 lumens. In Low power, the output dropped 17% to 448 lumens, still brighter than most 1080p projectors at full power, in their best (and dimmest) modes.
I was surprised by the 537 lumens, I expected more. This unit looks to be a full production projector (pre-production units often aren't quite as bright). The other difference might be that the RS1 when reviewed was brand new out of the box. This one had over 60 hours on it when I did my measurements, and as many say, the lamps loose brightness and shift color over their life, and more than just a little in the first 100 hours. It's purely conjecture, but had that RS1 had 60 hours on it, it might have measured 20 or 40 lumens less, but I'm just guessing.
The important thing is the projector still had no problem with my 128" diagonal Firehawk G3. I think it will do ok with my screen thoughout its lamp life, but don't really think a larger screen will work unless you are fully darkened, dark walls/ceiling, for movie watching. And it is brighter than my RS1 is now (with over 1000 hours on the lamp). The point of this is, when I make screen size recommendations I consider that a projector won't be as bright as the lamp ages. Thus, if I say fine for 110" screens, I mean that the projector should still do a good job on a screen that size even as the lamp reaches the end of its life.
I digresss. Let's get back to the measurements.
n Natural mode the projectors brightness pretty much is unchanged, at 541 lumens. The difference is well within the measurement error range.
Dynamic gets a bit more boost, but, like with the RS1, not a whole lot. The RS2 measured only 54 lumens more - 591 lumens. All in all, the JVC RS2 has less lumens, and less punch than the RS1. The overall color balance of Dynamic is very good, much better than most equivalent modes on other projectors. That means you can probably squeeze out an extra 100 lumens without much trouble, by pushing up green and also blue, and sacrificing the black performance.
My impression, though, is that the higher contrast partially makes up for that. As a result, the RS2 stil seems to be a very bright projector. One thing of note, however, is competitive in nature. Last year the JVC RS1 was rather dramatically brighter than Sony's VW50. With the slight increase in brightness in the VW60, and the drop with the RS2, the new Sony is approaching the brightness of the RS2 in best modes, and is actually brighter in brightest mode. That should affect many people's thinking when choosing between the two. Last year, brightness would have been a big deciding factore favoring the JVC. This time around, the Sony's lower price might gather more attention.
RS2 Projector - Light Leakage
The RS2 leaks light out through the lens. In an almost pitch black room you can see a fair amount of light around the screen if there is no image. In reality, though, under normal viewing, you rarely will notice it, even with lighter colored walls. With a dark wall around the screen, you can forget about it all together. Bottom line - not a problem.
RS2 Audible Noise Levels
The JVC is rather average. In low power mode it is very quiet, and in high power lamp mode, it is a bit noisy, although not as noisy as the typical DLP projector, nor for that matter one or two LCD models such as the Epson Home Cinema 1080. On the other hand, many LCD projectors - notably the Mitsubishi's and the Panasonic, are almost silent by comparison. The noise levels are the same as the RS1, and I've been living happily with the RS1 running at high lamp power for quite some time. (In my room, the RS1 is mounted about 11 feet up, on the rear wall, about 8 feet behind me - so not very close). I should note that the RS2 also has a high altitude mode, where the fan runs faster (and louder). This is typical of almost all home theater projectors, but with JVC recommending using it over 3000 feet elevation, that's lower than most, which tend to spec between 4000 and 5000 feet.