I gave MarsEdit a bit of a rough ride earlier, but since 2.1 came out, I grabbed that for a fresh trial. It has support for a couple of features I was missing, notably MT tags and storing drafts on the server.
It's still not perfect, but just now, thinking about something else, my first instinct was to fire it up to write a bit about it.
Between that and the author's kind responses to my criticisms in that first post, I guess that means I should be looking for my credit card pretty soon. Hopefully Scrivener and MarsEdit will give me the tools to turn my thoughts into writing for a long time to come.