micron40,
You are correct about the Hz.
The LED Motion Plus is a little different than AutoMotion Plus, even though the terms are similar, they mean something different. So I'll explain those differences here.
LED motion plus used in our 81 series of televisions uses a breakthrough technology ‘Local Dimming’. The majority of LCD televisions use a cold-cathode fluorescent lamp (CCFL) to power the picture. This back light is unable to be turned on and off with speed. The 81 series is backlit (backlighted?) by an array of light emitting diodes (LED). Because of this, sections can be turned off independently and will greatly increase the black levels on the set.
So it helps with brigtness, panel bleed, and color variances as well as the darkest darks.
Now the 6-Series has 120Hz AutoMotion Plus, which fixes the inherent problem of motion blur. This has been inherent since the conception of LCDs. Traditionally, a CRT or other type technology will pulse the picture and and then go black - and the human brain can process this image. With LCDs, the image stays on the pixel until that individiual pixel is "told" to change to a different color, and the brain will process that "lag". Since LCD's can't pulse frames to reduce this, another way to improve the movement was to double the frame rate to 120 and have a frame of video repeated. So instead of inserting a black frame between the frames, we use interpolation which intelligently inserts a frame that is processed between the 1st and 2nd frame. That's the heart of AutoMotion Plus.
In turn, the AutoMotion Plus processing feature in the menu allows you to select the level of interpoloation that happens, thus customizing your picture based on the source that looks the best to you.
So that said, you will likely perceive less blur on the 6-series, particularly with video games and fast action. For slow scenes and picture quality, the 81 Series is an amazing picture, but will likely not respond to motion like the 6-Series would.
Combined, the 9-Series of our current lineup takes advantage of both technologies - LED Motion Plus and AutoMotion Plus.
I hope that helps explain the differences.
--HDTech