I've used one for years and definitely recommend them. I converted my late dad in his 80s and he said his dentist noticed the difference.
As PPs have said, they are often heavily discounted, I've never paid full price for one, and I stock up on brush heads when they are on offer.
I used to be quite dentist phobic and didn't go for a few years. The fact that I didn't need anything other than one filling when I eventually conquered my fear is, I think, partly down to the electric toothbrush. Having said that, my way of dealing with my phobia is to be a bit obsessive about my teeth - I floss, have the tepe brushes and a water flosser, and I brush after every meal. It's working though - I only have three fillings and great gum health.