Matter of personal taste when choosing the "better" one.
Passionate is basically her embracing the love and sex with protagonist.
Permissive is more of a... How do I describe this? Basically she allows the sex stuff, but she loves him as a mother and unsure about this whole thing, but can't really do anything about it.
Think of Martha and her guilt stat as a main thing when in Permissive state.
And her being Passionate, at least that's how I see it, removes the point of guilt(like, the whole "this poor boy didn't get enough attention from me for so many years, so I better pamper him" thing) stat and allows her to focus on her own needs and desires without regrets.
Hope it makes sense