Electric toothbrushes, useless fad or genuine progress?

Definitely genuine progress, but get a decent one, I like the Braun/Oral B range. DON'T get a flashy model with BlueTooth and a back scrubber attachment. Here's the check list:
1. Easily available replacement heads.
2. Decent battery technology, Nickel Metal Hydride not NiCads.
3. Timer. Two minute timer to check you are going for long enough.
4.  Err. That's it.