I’m surprised that you’re able to find 2027 plans right now. Everything I’ve seen tells me that you can shop for new plans beginning October 15. ETA: I just logged onto the Medicare site, and, yes, I can already shop for Part D plans. So thanks for the heads-up!
It’s been my experience that, yes, Part D plans can vary widely in their cost and coverage. And I’ve always chosen the cheapest one; thus far, with no repercussions.
There’s an ongoing discussion about All Things Medicare in the link below. It might be better to participate in that thread, rather than opening a new one.