This is a very good question and I have had that question my self. I know the lower the model number the less advanced it is. But the lower the model number, does that also reflect the age of the tv as well? I dont know. For example I was in target the other day and they had a 600 series on sales for 2199, now i was not even aware that they made that old of a series. So for those here who know, and there are people here who know the answer to this I will learn as well as you will. I did read an article that each new series fixed something in the previous model lineup. Now that is great, but the question for me remains is this, is the 600 a 2011 model? What about the 700 and 800 series, are they also 2011 models or doe they split between 2011 and 2012? That I don't know but would love to know the answer.