As a patient advocate I often help people who are struggling with understanding and accessing their healthcare options. As you can tell by my other posts on this, I discourage people from choosing Medicare Advantage plans, as they are very misleading and limit you from choosing the doctors, hospitals and specialists you want or need to see. You are signing over your Medicare benefits to them. Often pre-authorization is required, which delays care and may be refused.
This is ESPECIALLY true of Kaiser. It sounds great, everything under one roof, and possibly cheaper, which is great when you are well, but if you need specialty care, all referrals within Kaiser have to come from your primary care, and they are often reluctant to refer and patients often need to be stout advocates for their own healthcare. If you need to go outside of Kaiser for care, it is an uphill battle. Fully 60% of the calls I get are about people struggling to get the care they need at Kaiser.
In contrast, with "traditional" Medicare you can see any doctor without referral and the majority of providers accept Medicare.
Following are excellent informational links to help you understand the differences. Also, in CA there is HICAP, which offers one on one counseling to help you choose your Medicare plan and supplementals.
Medicare.gov
HICAP (California)
https://cahealthadvocates.org/hicap/
Free counseling for other states: