I'm not impressed with all the ultrasonic technology, personally. I have bought and tried a clarisonic, and an ultrasonic toothbrush. Neither gave me the super clean feeling they bang on about. My dentist said that a good quality electric toothbrush is better, and my own experience is that is true. I think the current state of the technology available is the early (cheaper) technology, and eventually there will be a better version that will be worth paying for.
On Clarisonic etc, there are unabashed fans, but some skincare experts think they over clean the skin and cause a new set of problems instead of the old set. I expect that if you are going to be slathered in heavy makeup, spending time in deeply polluted areas (underground transport systems for example) there is a benefit, but for some it will fall into the sledgehammer to crack a nut category.