Choosing the best Medicare Supplement (Medigap) insurance plan depends heavily on your medical needs and budget. Plan G is widely considered the best and most comprehensive choice for new beneficiaries because it covers all out-of-pocket costs except the annual Part B deductible. Plan N is an excellent lower-premium alternative that requires small copays for certain office and emergency visits. Top-rated national carriers offering these standardized plans include AARP/UnitedHealthcare, Mutual of Omaha, and Cigna.