>>...I have not found nested ifs clear and obvious in most situations that I have seen them. I do still prefer "not cases" as I can maintain them better - e.g., if one particular case fails and requires special handling in one caller only (I've seen this more than I thought I ever would), it's easier
to add the handler code/call to the case.

I agree with you.
I find complicated nested-ifs very difficult to maintain.
I much prefer to code "not cases."