Actually I switched to electronic toothbrush years ago as it cleans better. Now when I am deprived of my brush and have to rely on a normal brush I don't feel like I did good job cleaning my teeth. Part of this may be subjective feeling but various tests show that electronic toothbrush cleans better than regular one in most cases.

No, I don't need any special functionality other than to clean my teeth but if you were to design a toothbrush you would most likely be asked to implement those.