Been reading about this little guy in other forums and decided to give it a shot with my PT-AE8000U and...
Dang! It really does work. I'm using it at 75% green mode, and turning on the Darblet appears to focus the picture well beyond what the optical focus of the projector can do by itself. I know it's in some sense an illusion, but this illusion is perceptually dramatic. I currently have my Detail Clarity set at +7, and the combined effect is just stunning, with no artifacting that I can discern. It never looks overprocessed, it just looks better. I can also tell you that Darblet will do it's thing no matter what Detail Clarity setting you have, it will just incrementally increase perceived focus/sharpness at all settings.
I bought it from Amazon so I could return it easily if I was not impressed. I will not be returning it.