VIVO cards might be different, but even going through S-Video on tv-tuner cards is crap.
I've had both the Leadtek TV2000 Expert and now the Hauppage Winfast PVR-250 and both have been quite disappointing in their ability to manage signals other than coax (which, needless to say would be very ugly if you used it). The Leadtek had decent, but nowhere near normal composite quality picture. Plaing anything with much movement caused noticeable blurring. The PVR-250 is absolutely pathetic. It was so bad that the card was causing seconds of delay. For instance, I was playing Project Gotham. When I would steer it would take about 2+ seconds to actually start turning on the screen, which needless to say makes the game unplayable.
My friend has an AIW 9700. I'm not entirely sure how he has his PS2 connected to it, but the image quality is very bad. I've watched him play several games that have nice graphics and they look like he's playing PS1 or N64.
This is just what I've encountered.