She is a retired teacher in Illinois. Illinois eliminated post-65 coverage for retired teachers several years ago offering a non-subsidized Medicare Advantage plan in its place. The Medicare Advantage plan is a United Health Care group PPO plan with features negotiated by the state on behalf of the group, but not subsidized. (DW has the Medicare Advantage premium deducted from her pension check and the fed gov't bills her for the Part B premium.) Her alternative was that or simply walk away and go with traditional Medicare and a supplement.
I would have had her go with regular Medicare and a supplement but it was her choice. Thankfully, it's a PPO style Medicare Advantage plan (not HMO style) and despite utilizing a lot of providers and specialists this past couple of years due to her cancer, there have been no issues, no restrictions, no refusal of providers to accept the coverage and no surprises.
Other than the absence of the infamous "donut hole" in her drug coverage and the minor perk of Silver Sneakers paying for her health club membership, I haven't seen any advantages over regular Medicare + supplement. But, OTOH, I haven't seen any disadvantages beyond me needing to know the ins and outs of two different programs.
Inexplicably, customer service has been extraordinarily good. Far superior to my BCBS type F plan where phone trees and long waiting times are the norm.