I think the 57 is an older generation, it doesn't seem quite at the 96 series level, but I have not been able to tweak it, can't tell for sure. It does look pretty good at the Magnolia, but they won't let me touch the thing. It's an awfully big set.
The 52 is really great if you sit about 11 feet away. At 9 feet it is sometimes a bit too grainy, but on a clean feed it is pretty good. If you are really picky about black crush, you may have a problem. I have been able to set it up, not a cal like Doug, but good enough to make me feel pretty good about the purchase.
One thing, the backlight does have some blotching at black in a dark room, but for almost all viewing the uniformity is outstanding, 10/10. Color tracking, well some ice scenes have some pink, but its not a big deal for me. It does HD ice hockey very well on a clean feed.
The key is good feeds, I feel the feeds will only improve over time so this tv has a great future, will put out good images for a long time I believe, given that it holds up.
HDMI has overscan. Since it will not be a monitor, it's not a big issue at all. The scaling is excellent, 1080i looks fantastic given a clean feed. Digital SD is ok, my Sony DVD NS-90V is set to 1080i. The results via HDMI are the best I have ever seen with DVD. Don't worry about the scaling, this machine does it very well, you will not be disappointed.
There is some viewing angle washout, but only significant with dark material. At 3 screen widths, clean feed, this thing looks like a plasma. I don't own plasma, but I feel its still the pic to beat. The 7 year itch is playing on INHD now, unreal, classic movie in widescreen HD. Colors still don't rival plasma, though. Good luck, I think you will love the 46 or 52.
Keeping DNIe on and cranking up the brightness works for me with this set.