The next thing that differentiates vendors of the same plan is how long have they been in the marketplace and how stable has their fee structure been. Have you ever heard of the term "loss leader' as applied to marketing. When a new vendor enters a particular market, they are free to lower their price as they see fit. Sometimes this is done to gain market share. They are also free to raise prices when they see fit. ALL prices go up for ALL vendors. The cost of healthcare hasn't went down now has it? But some vendors play with prices as a marketing tool. Well no problem you say? you will just change vendors when ever you want and shop for a better price? UM, NO. Not always. You MAY be able to price shop at a later time BUT you must be in good health to do so. If you health is not good, you must pass underwriting. And that is not an easy thing to do for many people with chronic illness. While you can be nearly dead during your initial sign up period (3 months prior, the month of and 3 months post of your 65th birthday) And no insurance company can refuse you. When you want to go price shopping later it is a different story. You better be healthy. This makes choosing a vendor a VERY important decision. So yes, all plan G's cover the same things, and are offered sometimes at different prices, the vendor can make a huge difference.