I am not a dual citizen, but know several. The benefit is that you have all the rights of a citizen in either country, the chief benefit is that you can stay in either country as long as you want to, and not worry about any visa limits.

The main drawback is that you are subject to all of the regulations in both countries, and if you get in some sort of legal trouble in one country, the other country can’t help you at all. (Of course, they may not have helped either way).

If you are a citizen of a country, you often must show that passport when entering. So these people frequently travel with both passports, and when going to a third country, use whichever one is most advantageous.