I've read through the vast majority of this thread when deciding a TV to purchase. I took delivery of the 55inch M series on Thursday. I calibrated using Shankensteins settings from page 19, and use Game mode.
That being said... I think I'm having a bit of an issue.
1) I can't tell if this is ghosting or an issue with the dimming / backlighting. If the screen is all black and a white letter pops up on a region of the screen, a certain portion of the screen will have a white haze, or what I would call ghosting (not sure if this is appropriate use of "ghosting"). If, for instance, the playstation loading circle in the top right pops up, the top 1/3 - 1/4 of the screen has this white haze, making the rest of the TV perfect black and this small portion a dark gray.
2) I've also noticed when I use my Xbox 360, and I log in, there is a background greyish / white loading screen with a circular loading symbol in the middle of the screen. As the loading symbol spins (in the exact middle of the screen), it makes the entire middle of the screen (horizontal) kind of blink. Where it blinks corresponds to the direction in which the loading symbol moves.
3) The day the TV was delivered, while watching the TV, a green bar popped up on the left side of the edge of the TV. Turning the TV off and on made it go away. When the green bar popped on the edge of the screen, there was a slight audible noise, which is why I'm bringing it up. Has me slightly concerned. I have photos I will post a bit later.
4) I think this is common, but sometimes I notice the side edges of the TV being a bit darker than the rest.
I left my pictures at home, but will post them when I get home this evening. I'm curious if this is just how this technology works, or if this is a defect of some kind. Short of those issues, the TV looks amazing. 3D looks great. Blu-Ray of Avatar was just jaw dropping compared to my 2007 XBR sony bravia 40 inch. An enormous step up.
FYI - Amazon is offering $100 off of this TV for Amazon Prime members. You can simply sign up for a free trial of Amazon prime to take advantage of the offer, and then cancel. I also signed up for the Amazon Credit Card which provides an additional $50 gift card to put towards the TV. I'll be cutting that card up when I get it. I ended up paying a total of $898 for the 55 inch M series, as there was no sales tax. Ordered on Tuesday, delivered Thursday morning.