I read a newspaper article who did a survey on toothbrushes. The results found that the battery operated ones (fairly cheap) performed just as well as the really expensive ones.
Any electric toothbrush is better than a manual one so my dentist says.
Hope that helps.
The Sonicare toothbrush is the best toothbrush on the market. I use one and it's improved my oral hygiene - no more fillings and saved me money!!! It also leaves my mouth feeling fresh even after a cup of coffee. Good investment