The BeoVision 9 is a very good television with few, if any, of the image effects seen on most flat panels. Especially moving objects appear to be just that. Even today with the 7-55 on offer the discontinued BV9 can compete. Sure, the black levels of the 7-55 is a notch better - but the dynamic back light on the 7-55 is a bit strange sometimes when you are used to the (Panasonic) plasma in the BV9: Watch a concert on the 7-55, and pay attention to the audience when a flash goes off - a much larger (compared to the single person holding his/hers camera) circular backlight appear and, well, doesn't look right.
Another bonus is the fact that my Sony Bluray connected to the BV9 gives me DTS HD Master Audio, which often is the only HD audio source on offer on bluray's. With my BeoLab 5/9 setup the difference between selecting regular DD 5.1 or DTS HD Master Audio is night & day! Do not know why so few discs come with Dolby True HD... The built-in bluray in the 7-55 can not decode/reproduce DTS HD Master Audio. A big drawback if you want the best movie experience.
Also, if you need ALT the 7-55 will be a lot taller with the BL7-4 compared to the BV9 with its compact custom built BL7-4.
There are drawbacks with the BV9, but none related to audio and video reproduction IMHO: The fact that you can not split it for transportation makes it very difficult to move. The plasma panel produces a lot of heat, and as it warms up you can hear ticking sounds due to expansion. And the power consumption is approx 500 watt when turned on.
Roger