Through internet research, I am able to concur that there is no difference between the NBR-12 and the 1201. Both seem to be one in the same. Providng 600 watts and the same items for utilization of the device.
Honestly, I don't know. I bought the NB101 and it looks exactly the same as the 12 and the 1201. Maybe speed? I use my NutriBullet for milk shakes (with fruit), and juices (with vegetables) and it makes them so deliciously smooth.