They are also highly recommended for elderly and people with arthritis and hand problems.
The ultrasonic ones also help a bit better with detaching the plaque from your teeth.
Having said that, if you brush the right technique with good 4-5 min After every meal, manual is as good. Also, if someone has sensitive gums or teeth,manual would be a better option.
Typically you want to brush for 2 minutes and wet the brush head. Angle the brush head at a 45 degree angle into your gums and roll out toward the crest of the gums.
Have fun brushing (first flossing) with ur new toothbrush!
Hope this helps!