Comparing the two 65s, the Sony is definitely the superior set. That XBR is a full-array LED set with local dimming, the Samsung D8000 is edge-lit LED with ineffective pseudo-local dimming. As such it will have generally weaker black levels and more backlight distribution issues than the Sony.
As far as the motion handling, I don't think anybody really knows for sure what exactly Samsung's "Clear Motion Rate" numbers (480, 600, 720, 960 on the D8K) or Sony's MotionFlow ratings (XR240, XR480, XR960 on the HX929) are meant to represent. Neither company manufactures sets that have an actual refresh rate that exceeds 240Hz, but they're probably factoring in backlight scanning/strobing + black frame insertion systems to arrive at higher "perceived" refresh rates, hence the higher numbers...mostly marketing speak to pander to "spec sheet" buyers. Same for contrast ratio; the numbers mean nothing here.
ht Panasonic TC-P60ZT60, Monitor Audio: Silver RX6, RX Centre, Radius 90HD; Martinlogan Dynamo 700, Marantz SR5006, PS3, Oppo BDP-103D
2ch Marantz PM8004, Sony BDP-S1000ES, JVC T-X3 tuner, Monitor Audio Silver RX1, REL T3, Apple TV, Peachtree Audio DAC•iT
lr Panasonic 50ST60, Sony BDP-S5100