Choosing the best medical insurance for visitors to the USA depends on various factors, including the visitor's age, health condition, length of stay, and specific needs.
Here are some popular options and considerations for medical insurance for visitors to the USA:

1. **Visitor Insurance Plans:**
   - **Atlas America:** This is a comprehensive travel medical insurance plan that provides coverage for medical expenses, emergency medical evacuation,
and repatriation.
   - **Patriot America Plus:** Another option that offers comprehensive coverage for visitors to the U.S., including coverage for acute onset of pre-existing conditions.

2. **Travel Medical Insurance Providers:**
   - **IMG (International Medical Group):** IMG offers various travel medical insurance plans, including those tailored for visitors to the USA.
   - **Seven Corners:** Seven Corners provides travel insurance plans, including options for visitors to the U.S.

3. **Considerations:**
   - **Coverage Limits:** Look for plans with high coverage limits,
especially for medical expenses and emergency evacuation.
   - **Pre-Existing Conditions:** Check if the plan covers pre-existing conditions or has a waiting period for such conditions.
   - **Deductibles and Co-Insurance:** Understand the deductible and co-insurance requirements, as these impact your out-of-pocket expenses.
   - **Emergency Evacuation and Repatriation:** Ensure the plan covers emergency medical evacuation and repatriation of remains.
   - **Duration of Coverage:** Choose a plan that aligns with the duration of the visit.

4. **Comparison Websites:**
   - Utilize comparison websites that allow you to compare different travel insurance plans for visitors.
Examples include InsureMyTrip and Squaremouth.

5. **Consult with Insurance Brokers:**
   - Insurance brokers can provide personalized advice based on your specific needs. They can help you navigate the available options and find a plan that suits your requirements.

6. **Customer Reviews:**
   - Read customer reviews and testimonials to get insights into the experiences of other visitors with a particular insurance plan.

Remember that the "best" plan can vary based on individual needs and circumstances. It's crucial to carefully read the policy terms and conditions, understand the coverage details, and ask questions if needed. Additionally, make sure the insurance plan complies with any visa or entry requirements.

Before purchasing any insurance, consider consulting with an insurance professional or seeking advice from a travel health insurance expert to ensure you choose the most appropriate coverage for your specific situation.