Hopefully I'll end up with a solution for the Blu-Ray handshake issue because it would be a shame not to be able to use this thing, now that I've experimented with it.
I think I'll just be repeating what everyone else says if I describe what it seems to do. At first I was a bit underwhelmed is inserting it into the chain. I did notice a difference in sharpness (on Hi-Def and Pop modes) but not necessarily a "wow." It didn't immediately seem like it was a difference I'd know was there unless I actually A-B'd the processing in on/off mode.
But over time I really came to appreciate it's effects as I watched more material I'm familiar with. Like everyone else says, the effect is to sharpen up the image and along with that increase the sense of dimensionality in doing so, but pushing the settings too high can start to make the image look obviously enhanced, where I can't help but be thinking I'm seeing the Darblet processing rather than how the actual image was shot.
Although I haven't done a lot of testing in the "Pop" mode, I did notice it tended to add a more aggressive look, with more obvious haloing or rising of the bright contoured areas, whereas the Hi-Def mode was more subtle - the brightness of the neighboring brightness areas wasn't pushed as bright, but it was still enough to increase the perception of sharpness and depth.
So I stuck with the HiDef mode, and tended to use between 30 to 70 percent adjustment, mostly around 35 to 50.
Even at a setting of 30 when I A/B the image it looks like, as others have said, a scrim of softness is removed from the image with the Darblet engaged. Clearer detail, like putting a better lens on the image.
As I've mentioned, I own the JVC RS55 projector, which does an optical/processing trick of increasing pixel count to 4K, and then offers it's own level of processing to further increase sharpness and dimensionality. The processing is merely under the label "MPC" settings, from 1-3. Like the Darblet, these MPC controls do not seem exactly like sharpness or standard detail enhancement controls (the JVC offers those separately as well). The processing seems to do something similar to the Darblet: some sort of playing with gamma or contrast at fine levels, to bring out visible detail, sharpness etc. Putting the MPC levels at +3 really does subtly but distinctly make the image look more dimensional and sharper, like you can see all the way into the background for fine detail.
Since the Darblet would be expected to have a similar result I wanted to compare the two. I chose a scene from Avatar, the shot were Steven Lang (Colonal Quaritch) finishes pumping weights and sits up to talk to Jake. It's a nice long shot with tons of available detail, with his figure against a fairly dark background - great for increasing dimensionality.
This showed what I liked and didn't like about the Darblet processing. The overhead lighting on Lang places fairly bright highlights on his nose area. This is just the type of area in an image were, if calibration or processing is aggressive (e.g. contrast set too high, clipping etc) you start getting that too stark or clipped white cheaper video look to an image, vs a more balanced film look. As I turned up the Darblet and the contrast increased, Lang's skin became more palpable and "there" and detail came out in his hair and face. But at the same time those bright highlights around his nose started becoming so bright and pronounced they became distractingly artificial - it started looking pushed, processed, unnatural and more video-like vs film like or real.
This was a sort of worst-case scenario type shot for the Darblet in terms of introducing this effect, but I wanted to get a good idea of what is going on.
As I remember, the Darblet dialed to around 30 or 35 visibly increased image clarity on this shot, while not looking too video like. But if I were to take the movie as a whole, I could leave it dialed up higher, say 45 to 60, and in most instances it made the image more detailed and clear without screaming "processing."
In comparison, the JVC RS55 projector's MPC processing was, to my eye, more natural and subtle. Dialing it up increased the perception of image detail, dimensionality etc, but looking directly at details like those nose high-lights, they did not start "burning up" in intensity in any obvious way and didn't seem to alter the integrity of the image as much. But then, it also doesn't offer the degree of enhancement the Darblet offers, and I really came to appreciate the extra kick of the Darblet on various material, including sports (like the UFC).
For me the real "aha" moment was when I finally tried the JVC's MPC processing in combination with the Darblet. Taking that Avatar shot I spoke of, and a few others like close ups of Jake's face, I dialed up the Darblet to just were it was enhancing the image, but once it started to give an obvious high-lighted effect, I backed off. But then I started to engaged the projector's MPC settings and I saw the clarity and detail further increase but WITHOUT the Darblet's cost of the high-lights getting too artificial looking. It was like putting on that final lens when getting my eyes tested that snapps everything into perfect focus.
For me this is when the image on my screen really took off. It was just astoundingly clear and sharp, but generally there was very little additional image noise (in fact I started to wonder if the Darblet does any noise reduction, since it somehow made the MPC processing look even smoother than normal). Movies like Alien still looked quite cinematic, but with a Holy Cow new level of solidity, clarity and dimensionality.
Although my system is set up to zoom images to various sizes, I recently bought a second hand Panamorph UH480 anamorphic lens so that I could make CinemaScope images even larger on my system (up to about 125" wide, from between 9.5 to 10.5 foot viewing distance). The larger you make any image in relation to a given seated viewing distance, generally image snap and sharpness tends to decline. What is particularly wonderful about introducing the Darblet (along with the MPC processing) is how it allows me to increase the perception of image sharpness/clarity to compensate as the image gets bigger. It was just amazing to re-view scenes from Start Trek (2009), Casino Royal, King Kong, Transformers etc
and see a pin-sharp image of incredible detail at that size. It looks like the clarity I'm used to of smaller image sizes, but retained at any size.
Though I still noted the need for caution on my part - putting up the settings to "wow" mode, e.g. for me between 50 and 70 - could work with some shots, but others like certain facial close ups could look a bit harder and harsher, saying "image processing" to me. I'll have to find the balance.
I also note that turning the Darblet up beyond 45 or so can either start to introduce obvious white line/ringing on some outlines, or perhaps simply enhance existing source ringing that was already there.
But the enhancement form the Darblet doesn't simply seem to be just "sharper and clearer." The way it seems to achieve it by altering contrast also seems to increase the general sense of, for lack of better words, ANSI "pop" and MTF. For instance the various stars against black backgrounds, street lamps in night scenes, bright futuristic graphic computer displays (Avatar/Alien), brightly lit buttons (e.g. the crew turning on controls in Alien), highlighted rain drops on windows (Jurassic Park T-Rex scene in the cars) all take on greater contrast and intensity and "pop" so it's sort of like upping the contrast look of the image overall. It can be pretty dazzling, but again, can walk the line between "real" and "film" depending on one's goal.
And it definitely made the UFC's I've recorded look sharper, though for some reason when I tried dialing the processing much higher (e.g. toward 100) it started to make the contrast look to my eye a bit more unnatural and crushed, so I dialed it back a bit.
All in all, though my experience with the Darblet has been brief, I'm extremely happy I purchased one. It adds a wonderful tool to the kit for dialing in my system, and increasing apparent image clarity and quality. Like getting new, better lenses, or somewhat upgrading the projector, but for a ridiculously lower cost. And for someone like me looking to preserve the integrity of the film image while increasing dimensionality and clarity, the combination of the Darblet and the projector's MPC settings is the magic bullet.