Which is better and the most effective tylenol (acetaminophen) or excedrin for tension headache / migraine?

Depends: Excedrin contains tylenol (or acetaminophen)/caffeine/aspirin. For some people, tylenol alone can help with their headache. For more severe headache/migraine, excedrin might help better since it has caffeine which helps to constrict your blood vessels. In both cases, it will not treat/cure your headache, but it will help with the pain.