I'm surprised to not see a thread here on SDN about ultrasonic toothbrushes. I've just come across Emmi-dent 6 online. I was wondering what everyone is thinking about them. The ultrasound technology seems really benefiting to me.
I have an ultrasonic one and I love it! It's not the one you mentioned though. The sonic waves break up the plaque better than a standard toothbrush that's why they're so much more expensive. I would definitely recommend it though!