Medicare Advantage — the private insurance alternative to Original Medicare — now covers more than 33 million Americans, according to CMS.gov data, representing roughly 54% of all Medicare-eligible beneficiaries as of 2024. That number has grown every single year for the past two decades, and the plan options have multiplied right along with it. In 2024, the average Medicare beneficiary could choose from 43 Medicare Advantage plans in their county, a figure that has since stabilized slightly as some insurers pulled back from unprofitable markets. With that many options, picking the right plan isn't just confusing — it can feel impossible. But there's a framework that cuts through the noise, and it starts with understanding what separates a genuinely good plan from one that just looks good on paper.
The CMS Star Rating system is the most important tool most beneficiaries never use. Every Medicare Advantage plan is rated annually on a scale of 1 to 5 stars, with 5 being the highest. These ratings measure dozens of factors: how well plans manage chronic conditions like diabetes and heart disease, how quickly members can get appointments, how often preventive screenings are completed, and how satisfied members are overall. According to CMS.gov data, in 2024 approximately 32% of Medicare Advantage enrollees were in plans rated 4.5 or 5 stars — a meaningful benchmark. Plans that earn 4 stars or higher for three consecutive years are generally considered reliable. Plans rated 2.5 stars or below should raise serious red flags, and CMS has the authority to terminate contracts with chronically low-rated plans. Before you look at a single premium or benefit, look up your plan's star rating at Medicare.gov.
UnitedHealthcare is the largest Medicare Advantage insurer in the country, covering roughly 29% of all Medicare Advantage enrollees as of 2024. Its AARP-branded plans — marketed in partnership with AARP — are available in nearly every county in the United States, which gives it an unmatched geographic footprint. UnitedHealthcare's network is broad, and many of its plans include extras like gym memberships through Renew Active, vision, dental, and hearing benefits. However, size doesn't automatically mean quality. UnitedHealthcare's star ratings vary considerably by region — some local plans earn 4 or 4.5 stars, while others have hovered closer to 3 stars. If you're considering a UnitedHealthcare plan, look up the specific plan in your county rather than assuming the national brand translates to local excellence.
Humana is the second-largest Medicare Advantage provider and has historically earned strong star ratings, particularly for its HMO plans in the South and Southeast. Humana's Gold Plus HMO plans in states like Florida, Texas, and Kentucky have frequently earned 4 or 4.5 stars. Humana also offers a robust chronic care management program and has invested heavily in in-home health services through its CenterWell brand. One thing to watch with Humana: its PPO plans, while offering more flexibility to see out-of-network providers, often carry higher cost-sharing than its HMO options. If you have a primary care doctor you're not willing to leave, verify network participation before enrolling — Humana's HMO networks can be narrower than they appear in marketing materials.
CVS Health's Aetna division has aggressively expanded its Medicare Advantage footprint since the 2018 merger, and it now ranks third in enrollment nationally. Aetna's plans tend to be competitively priced, and the company has leaned into its MinuteClinic network as a supplemental care access point — useful for beneficiaries in suburban and urban areas. Aetna's star ratings have been mixed in recent years; the company lost its 5-star status on several plans following CMS methodology changes in 2023. That said, Aetna's SilverScript drug plan integration can be an advantage for beneficiaries who want streamlined prescription drug management. Always check whether your specific medications are on Aetna's formulary before enrolling, because formularies change every January 1.
Elevance Health — formerly Anthem — operates Medicare Advantage plans primarily through its Blue Cross Blue Shield affiliates in states like California, New York, Georgia, Virginia, and Ohio. Its plans tend to perform well in markets where it has deep provider relationships, and its BlueCard network can be valuable for beneficiaries who travel frequently. Kaiser Permanente, while only available in about a dozen states and Washington D.C., consistently earns the highest star ratings of any major insurer — frequently 5 stars — because its integrated model (where the insurer and the medical group are essentially the same organization) eliminates many of the coordination problems that plague other plan types. If you live in a Kaiser service area and are comfortable with an HMO model, it deserves serious consideration.
Beyond the brand name, the plan type matters enormously. Health Maintenance Organizations (HMOs) require you to use a specific network of doctors and hospitals and typically require referrals to see specialists. They usually have lower premiums and predictable cost-sharing. Preferred Provider Organizations (PPOs) let you see any Medicare-accepting provider, but you'll pay more for going out of network. Private Fee-for-Service (PFFS) plans set their own payment terms, and not all providers accept them. Special Needs Plans (SNPs) are designed for people with specific chronic conditions, dual Medicare-Medicaid eligibility, or institutional care needs — and they often provide more targeted benefits than general Medicare Advantage plans. If you have a serious chronic condition like congestive heart failure, COPD, or diabetes, a Chronic Condition SNP (C-SNP) may offer better disease management support than a standard HMO or PPO.
The out-of-pocket maximum is one of the most underappreciated numbers in Medicare Advantage. In 2026, CMS caps the in-network out-of-pocket maximum at $9,350 for Medicare Advantage plans, and the combined in- and out-of-network maximum for PPOs is $14,000. These are the ceilings — individual plans can set lower limits, and many do. A plan with a $3,500 out-of-pocket maximum is meaningfully more protective than one set at $8,500, even if both advertise a $0 monthly premium. If you have ongoing health needs — regular specialist visits, prescription drugs, physical therapy — run the math on your likely annual costs under each plan, not just the monthly premium. Medicare.gov's Plan Finder tool lets you enter your specific drugs and doctors to generate a personalized cost estimate.
Data Snapshot: According to CMS.gov data from the 2024 Medicare Advantage and Part D Star Ratings release, 57% of Medicare Advantage enrollees were in plans rated 4 stars or higher — up from 51% in 2023. However, the number of plans receiving 5 stars dropped from 74 in 2023 to just 31 in 2024, reflecting CMS's tightened methodology. This means that while more people are in higher-rated plans overall, truly top-tier 5-star plans have become rarer and more geographically concentrated. Beneficiaries in rural counties are statistically less likely to have access to a 5-star plan than those in major metropolitan areas.
Extra benefits — dental, vision, hearing, transportation, over-the-counter allowances, and meal delivery — have become major selling points for Medicare Advantage plans. But these benefits are not standardized, and their actual value varies wildly. A plan advertising 'dental coverage' might only cover cleanings and X-rays, with no coverage for crowns, bridges, or dentures. A plan offering a $500 OTC allowance might restrict it to a narrow catalog of approved products. Before you choose a plan based on its extras, read the Evidence of Coverage document — not the marketing brochure — to understand exactly what's covered, what's excluded, and what the annual dollar limits are. The Evidence of Coverage is a legally binding document; the brochure is not.
Enrollment timing is critical and non-negotiable. The Annual Enrollment Period (AEP) runs October 15 through December 7 each year, and any changes you make take effect January 1. If you miss this window, your options narrow significantly. The Medicare Advantage Open Enrollment Period (OEP) runs January 1 through March 31 and allows you to switch from one Medicare Advantage plan to another, or drop Medicare Advantage and return to Original Medicare — but you cannot use the OEP to switch from Original Medicare into a Medicare Advantage plan for the first time. Special Enrollment Periods (SEPs) are available for qualifying life events: moving out of your plan's service area, losing employer coverage, or qualifying for Extra Help with drug costs, among others. If you're newly eligible for Medicare, your Initial Coverage Election Period (ICEP) begins three months before your 65th birthday month and extends three months after.
One final consideration that doesn't get enough attention: network stability. Insurers periodically drop hospitals and physician groups from their networks mid-year or at the start of a new plan year. If your cardiologist or oncologist leaves your plan's network, you may face a choice between paying out-of-network rates or finding a new specialist. Before enrolling, call your most important doctors' offices directly and ask whether they accept the specific plan you're considering — not just the insurer's name, but the specific plan name and ID number. Networks differ between an insurer's HMO and PPO products, and they differ between counties. This one phone call can save you thousands of dollars and enormous frustration.