Per William Sommerwerck:
I've used the Sonicare for over a decade, and would never go back to a
manual toothbrush. It simply does a much better job.

Consumer Reports claims that a manual brush is /the/ best way to clean your
teeth and gums. If so, I don't know how to properly use one.

I never used an electric until about 10 years ago when my dentist
recommended them.

Up 'till then, I'd managed to scrub much of the enamel off of my
teeth by brushing too hard.

Since, there seems to have been no additional loss of enamel.
Also the ladies who do the cleaning at check-up time have
commented on how clean my teeth look.

I suspect that, in the end, it comes down to technique... but I
don't have it and the electric compensates.
--
PeteCresswell