The EB-5 Visa is a Green card through investment. Investors are given a temporary green card after two years. 10,000 applications are available per year. 5,000 of these is reserved for investments through the regional centers. Success rate for the EB-5 is quite high and generally depends on the investment type, personal situation, legal representation and regional center. The E2 Visa offers residency through substantial investment in a business. It is not a direct path to USA Green card.
EB-5 and E2 are not a citizenship by investment program, However; after getting a Green Card via the EB-5 visa route, investors can apply for USA citizenship after five years of Permanent Residency. This process is known as Naturalization.