I heard about the Byword app from Jeff at his “Optimize your Mac workflow” class.
First, I was a bit skeptical, because I thought writing is just writing, in markdown or not.
Turns out, it does matter. Writing in markdown is faster, since there’s no worrying about formatting it later, and Byword makes it easier to just copy&paste directly into WordPress.
Also, and this could just be my perception, the minimalistic look (grey background of the app, centered on screen, nice font) makes it easier to just focus on writing.
So now I’m a fan and highly recommend it. Well worth the $4.99 price.