I was kind of surprised when I read that some users were dissatisfied with the image quality on their BV8s. I believe scognamiglio was very unhappy, and remember I wondered about the strength of the signal he was using.
Today I was fooling around with the setup menu, and I tried the PAL output setting from my STB, instead of the RGB I had set it to originally. The image became very degraded. Where the RGB input results in an almost glassy, 3D image - the PAL input looked bad in comparison. Raster effects, bad contrast, watered out colours.
Which means you really have to ensure that you have set the right signal out of your STB or similar box, and that you have set your BV8 to process this correctly.