I believe Basic is the most popular FEHB plan? Maybe with retirees too? It appears to be outstanding coverage, different from most plans due to the set copays/coinsurance (which in my opinion might be its biggest appeal). It did have some significant cost changes this year (2023). Also I would like it better if it offered some Skilled Nursing days, and of course one has to be aware of out of network provider situations. The premium for self+one is heading for $500/mo, but if one doesn't have Part B too, the cost issue is perhaps mitigated for some.
There is also a statement in the Basic coverage to the effect of having to pay 30% of the plan allowance for agents, drugs, and surgical implants but I haven't found out which. Maybe this applies to certain outpatient (surgical or otherwise) situations? I wonder, 30% of what total cost?
Having said that, I recently looked at a publicly offered MA plan in my area which reminded me very much of Basic, has Skilled Nursing Days, a lower catastrophic oop than Basic, and offered about half the sample of common Rx I checked for zero cost, and with FEHB suspended, with a zero MA premium, it would only cost the Part B premiums per month as a basis. However, I would personally not want to do that. In my opinion, if the FEHB premiums keep going up, it could eventually cause some to have to drop their Part B and go with FEHB and Part A only. It sounds like this combo has worked well in your situation.