LG 47LM6700 vs 47LM7600

Hi, First time on this site and hoping to get some expert advise. I just bought the 47lm6700 and it is real jittery or motion blurry. I returned one because of the flashlight effect and the second one is has more of the motion blur. I found a 47LM7600 for 999.00 The 47LM6700 is 799.00 The sales rep said the 7600 is a better tv with a faster processor. Is it worth the 200 extra for the 7600? Will it have a smoother picture than the 6700? Also, should I invest in a Calibration CD like Disney WOW or Spears and Munsil. Im really am a novice at all of this. Any feedback is greatly appreciated.

Hi, I ended up buying the lm6700 first. then didn't like how gittery it was so I went and got the lm7600 both the 47 in models. To me out of the box the 7600 is far better. Image is a lot cleaner and looks great. Im taking back the 6700.