To those Americans who are looking into or have looked at Medicare and Medicare Advantage Plans, which did you choose and what was the cost?

I believe basic Medicare covers 80% of services (medical) and to cover the other 20%, you pay co-pays, does not cover dental or vision, and you need to purchase a medi-gap plan (cost can be $3000/yr or more). Medicare Advantage is a insurance plan from a company that has a premium but no co-pays and can cover dental and vision (if desired but that will cost you).

Any thoughts?