I nabbed Pixelmator last week as part of the Macheist bundle, and I have to say that it's quickly become my photo editor of choice for blogging-- it's quick, beautiful, simple, and perfect for what I need. Of course, what I need is mostly just resizing and cropping (with the occasional color fills or quick brushes), so I'm not a pro photo editor by any means, but as the creators said in our interview, it gets the job done.
And with the new patch 1.1.2, just released today, it gets the job done even better. The patch offers quite a few bug fixes, and a short list of interface tweaks and improvements. Selection tools have been beefed up, as have those color fills (they work in real-time, unlike before, you know, when they worked in fake-time). The update is now available for download over on the site, or should show up in the application as well.