I'm in the dental field. Here's my recommendation:
http://www.animated-teeth.com/electric_toothbrushes/b-best-sonicare-toothbrush.htm

Verrrrry helpful. Thank you. Reading about the fluid dynamics of brushing seems necessary to me. Call me crazy, but I just can't buy based on fluff and huff. I may need to learn more about brush heads. I've been using a compact one because I thought it reach more of the concave surfaces behind and around the "frames" of my teeth. Maybe that's a mistake - ?

I asked the dentist today when there'd be a whitening method for those with sensitive exposed roots, like me. He said never.

How can that be? Doesn't anybody want to get rich?

I have tried many electric toothbrushes and do not like any. But, I would like to take this opportunity to say that those toothbrushes with angled heads put far too much torque on my teeth. I have wanted to mention that to someone for years and somehow, the subject has just never come up :-)

Torque-on-Toothe -- isn't that up near the Lakes District?

Lol, jamies--- it must be near the Dentil Mountain range!

Yes, dentil for GW, triple wordplay :-)

Big, toothy grin...

There is a difference between brush heads. The round ones work best for me because my mouth is kind of small and I can focus the brush where I need it. Some brush heads have different fibers that get between the teeth much like flossing. We have a Braun Oral B; you can buy a variety of heads for it (all round).

I use the Oral B, also, with the round head and love that I can get the cheaper generic replacement heads for it. I do believe electric brushes clean better than a regular toothbrush. I wouldn't waste my money on the more expensive model...from what it says at the link bonnie provided, the updated features are for those who need more help or are always in a hurry.