+1 for Plan N. As I recall, it cost about $40 less a month (remember, that's almost $500 a year -- a couple of days of vacation) than G, and so far I don't make 2 trips to the doctor per month. On routine care it's less than $20: if the allowed amount is under $100, Medicare will pay 80% and then the copay will be less than $20.
The "excess charge" cannot exceed 15% of the Medicare-allowed amount; some states don't permit them at all. I've never seen one charged.
Here's something no one has mentioned: premium rates are either "age-based" or "community based." The former will increase every 2 years as you age, PLUS inflation. The latter start out at what seems a little higher, and they WILL go up because everything goes up, but they don't go up because you got older.
Where I lived in CA, the only community-based plan available to us was AARP-UHC. We switched onto that when Blue Shield announced "happy birthday, now pay more"; it cost $250/month for two of us, age 70. Now in Indiana, there are more community-based choices and the premium for the AARP-UHC is 22% less. I do recommend them; their website is clean and easy, and they pay promptly and reliably.