Pam, I've been on Medicare for 5 years, a few big operations, no problems. The key is to find an independent broker, JMHO the advantage plans are cheaper, appear to offer more but typically have high deductibles, additionaly there are restrictions if you want to leave the advantage plans and go to Medicare after the fact. Also ask if there are any restrictions on the advantage plans if you travel.
If you consider the Mayo at Jax an asset, make sure your supplemental includes it.