Ben Brooks wrote a very good review of the new iA Writer for Mac. It's a real-life review where he not only goes through the application, but also explains how he uses it in his workflow.
It looks like a beautiful app, which is important to me. If I'm going to be using something for hours I'd rather it was not only functional (that's a given) but also pleasant to look at. iA Writer seems to excel in both. Strangely, one thing I find really appealing is that it has no options. It is what it is and you can't spend hours messing with preferences. As Ben puts it:
The problem is that the more powerful something is — the more features you give the user — the more dangerous it is to tinkerers, and I am very much a tinkerer. Writer keeps me from doing any of those non-writing activities.
Exactly. If I counted how much time I've spent mucking around with the look of OmniFocus I would probably have a nervous breakdown.