Every Mac / Blogger I know raves about Ecto - I’m surprised it’s taken me so long to give it a try. There’s very little wrong with the WordPress native editor but sometimes (I know it’s hard to believe) you’re not online when you have the inspiration.
I’ll try it for a week and if all works as expected - I’d be happy to shell out twenty buck or so (which IMO is a reasonable price for a piece of software like this.)