As to choice of doctors, be careful and do your homework. At least in my area, there are docs who do not accept so-called ObamaCare, and others who do not accept Medicare / TriCare and the like. My docs (oncology and urology) will accept only one OC plan, and will accept Medicare only if you transition into it while already an active patient. My GP is considering next year, and expects only to accept regular commercial insurance and traditional Medicare (or cash).
And then there are those that you must choose from a defined list if you are in an HMO style plan. I've had some bad luck with company HMO style coverage.
I would call each current doc's office and ask what they accept / participate in. And by doc's name, not just the practice. And ask if they are planning any changes for next year.
Thesr are really good points!