Ok so after a few days with this set all i can say are good things except a few minor problems that can easily be solved.
First, the picture quality is simply stuning- looking at most TVs in best buy i quickly noticed that samsungs had a leg up on the competition in PQ this year and this set follows that trend. I've done no callibration but simply setting the TV to "natural" made my jaw drop. Extremely deep blacks, exquisite motion tracking especially for a 60hz, and superb sound quality (I have it set to "music") all add up to an stellar viewing experience. Im now having trouble getting my parents out of my room because they dont want to watch TV on their sony, that cost 500 dollars more than this set, anymore haha
I was timid about this TV due to no input lag tests but JESUS i didn't expect it to be this good. Everyone seems to say samsungs are bad for gaming but I can't tell the difference between this set on game mode and my old CRT. Im a huge COD player and couldnt have asked for a more responsive TV- It honestly must be about 1 maybe 2 frames of lag. Without game mode it probably jumps to ~2-3 frames of lag. Initially setting it to game mode made the picture dull looking out of the box but this set allows you to tweak some of the main picture settings while in Game Mode and now I honestly can't tell the difference from when i switch from HD DirecTV to my XBOX (im using component btw). The one complaint I do how however is the fact that game mode sets the sound to "movie" mode. When playing COD its hard to pick up on more quite sounds like footsteps and at the same time gun noises are blaringly loud. It reminds me of when i use my ipod tape adapter in my car- I normally set the ipod volume around 70% and adjust the volume on the stereo accordingly. Game mode on this set is like turning the ipod to full volume and blaring the stereo too: it just seems to take all the high pitch noises, distort them, and blare them at your face. I have to play with the volume on 10 and once i switch to satellite i turn it to around 30 just to give a frame of reference. Fortunately i plan on getting a sound bar soon so i can just route the sound through that and avoid the whole issue altogether.
The TV is gorgeous to look at aswell. They dont have that awful touch of color on the 5 series but still trim it with the thin outler line of glass/plastic. The stand is sturding and swivels and despite reading about the atrocious viewing angles on televisioninfo.com, I honestly dont see what they're talking about. I can get all the way to the side and still have decent picture quality.
All in all I would definitely recommend this set to the cost-sensitive buyers/gamers out there looking for the best bang for their buck. This is my first HDTV ive ever owned myself and Samsung is making a strong case for customer loyalty to say the least.
If anyone has anyone question about the D550 series i'll be happy to try and answer them to the best of my knowledge.