Medicare with Supplement vs. Medicare Advantage - I've done both
For 9 years I had original Medicare with a Supplemental Plan F (BCBS) and separate Part D. Over time the premiums for the Supplemental Plan rose so much that I finally decided to switch to an Advantage Plan. Chose one of the UHC Insurance AARP PPO plans. Worst decision I ever made. Continually had copays for everything from Specialists to Radiology to Outpatient Surgery and higher copays on certain medications. I'm still getting late bills from 11 months ago because my health system and UHC never got billing correct until now. My healthcare concerns became more about expense than quality of care.
I also was disgusted by the pressure to use the subsidiary of Optum Rx (United Healthcare owns United Healthcare Insurance and Optum Rx) which they continually spent my healthcare dollars advertising to me by telephone, email and USPS. My copay was so high for one generic (of which there are over 20 options), I switched that script to Mark Cuban's CostPlus and saved over $100 each time I got it filled.
(I highly recommend for all generics: https://costplusdrugs.com)
I have switched to an Aetna PPO and have same issues. The "free" OTC quarterly dollars (which obviously come from the moneys we pay in to the system) can only be used at CVS. Many of the OTC products I routinely use for eye care and skin care issues are not covered, because CVS has no own-brand product. Guess what the corporate relationship is between these two companies is.
Three new prescriptions prescribed by my new dermatologist and new ophthalmologist are not on formulary. The two options from the ophthalmologist were either $100/mo or $126/mo copay, so I'm not filling either. Fortunately a different generic form from the dermatologist was on formulary, so he agreed that I could switch, although he didn't think that form was as appropriate for me. In the past I was able to compare all available Part D plans annually and change to the one that would cost me least. With new prescriptions, that was still a crap shoot, but at least I knew what my costs would be for my ongoing meds.
Unfortunately I don't think I can get a Supplement Plan F anymore. And at my current age, the premiums are even worse than had I kept my old plan.
True, not one choice is right for everyone. But I had better healthcare options under original Medicare and regret switching to private insurance.