Most dentists recommend a smaller headed, soft-bristle brush. And all agree that an electric is better for most people than a hand-held. The oral-B electric is a fine choice. You do not need to spend more than thirty or forty dollars as the key is in the brisltes and not in the 'bells and whistles'.
the oral B 'pro white' rechargeable electric would be a good example of a fine brush for your purposes.
positive feedback appreciated.
please let me know if you have further questions.