It looks like Vizio streamlined this model to increase profits. The refresh rate is 1/2 the original. The color depth on this is 8 where the original model is 10 bit and the contrast ratio is 1mil to 1 where as the older model was 10mil to 1. I think they both use LED backlit technology.
KDE model MSRP: $799.99 (http://store.vizio.com/m3d470kde.html) 120hz and 16.7 million colors. KD model MSRP: $849.99 (http://store.vizio.com/m3d470kd.html) 240hz and 1.06 BILLION colors. These are the only differences between the two models. Both are 2012/2013 models and both are still in production and shipping as of Feb 5, 2013. This information was obtained from the Vizio website utilizing "online chat" direct to Vizio support.
Delta has no clue what they are talking about. No tv is pure LED format. LED is a lighting technology that is used BY LCD TVS. Some are edge lit (lesser quality) and some are backlit (better quality). Do research before you attempt to give others advice on where to put their money, Delta. No LED tv is without the LCD screen. U must have a screen to watch the pictures on. That's the LCD part of the equation. There are LCDs, LCD with LED lighting, and plasma. Mmmkay?