Which is better --- a manual toothbrush or battery operated?

Both: Any brush is good if used regularly and correctly. Most dentists recommend choosing a soft-bristled brush if you are using a manual brush. With power brushes one must take extra care not to be too aggressive, as the bristles tend to be hard. A power brush should only be guided and not leaned on. Try both and see which one works best for you. Just remember to floss as well!