Sony DVD madness.

So when I go to buy a DVP-S7700 my dealer tells me to save my money and buy the CX850 instead. He claims that the 850 came out later and has newer (and better - although he knows that they aren't synonymous) video reproduction technology. Thing is, I don't especially want a 200 disk changer. So I went back to the research drawing board and noticed that there are two single disk Sony solutions (S560 and the shiney S570) as well as 2 five disk options (C660 and C670). Now from what I understand at least some of these came out after the 850, and hence might have some of the newer filters and video DACs. What I want to know is how these six (7700, 850, 670, 660, 570, 560) compare in video reproduction (I'm not too concerned with audio reproduction as I don't tend to critically listen when I'm watching movies - I save it for the music). I'm mostly interested in hearing from people who have auditioned at least two of these as it's a comparison that I'm looking for. TIA.