Though both patterns help to take out object creation part from application logic, use of dependency injection results in cleaner code than factory pattern. By using dependency injection, your classes are nothing but POJO which only knows about dependency but doesn't care how they are acquired. In the case of factory pattern, the class also needs to know about factory to acquire dependency. hence, DI results in more testable classes than factory pattern. Please see the answer for a more detailed discussion on this topic.
