If you intend to live in the U.S. permanently, U.S. citizenship will provide you with a sense of security that you simply cannot experience with a green card. Citizens simply have more rights and privileges than permanent residents, and if you are hoping to gain some of these rights, then you might want to apply for U.S. Citizenship.
Only U.S. citizens can vote in elections and get to serve on a jury. Additionally, becoming a US citizen will give you the benefit of a U.S. Passport and ability to apply for federal jobs which are typically reserved for citizens only. U.S. citizenship will also afford you more educational opportunities and access to more scholarships and financial aid.