I've always adhered to the idea, that the less visible the pixel structure the inherently softer looking an image will be, all else being equal. The Sony, like the JVC, being LCoS, they have essentially invisible pixel structure, thus an apparent softness. This is also true of the Panasonic PT-AE2000U, an LCD, but one with their smooth screen technology which also makes pixels invisible at any normal seating distance.
While I refer to this section as sharpness, there are two aspects, - perceived sharpness, and actual resolving of fine details. As a general rule, even the softer looking images, show just as much fine detail as the sharpest (like the Mitsubishi HC6000, Optoma HD81-LV and Sharp XV-Z20000).