The lady on youtube, oh dear why bother.
She was comparing brush heads and did not even mention with the Clarisonic. The inner head goes in a different direction and you can click the outer part of the head off and just use the inner for round the nose and hard to reach places. The Nutrasonic is just a brush with no removable parts. Just the bristles on one are rougher than the other. As for the using on the body, she gave the idea the one she had with the facial brush could be used on the body. No, you need a different head for the body, which only comes with the Pro version as higher speed just for that.
Nothing about the speeds of each unit compared to the other.