I just bought this app because of MR's post and because the reviews have been stellar. The reviews are accurate. The repair/heal tool is AMAZING. It took me less than 30 seconds to edit this photo from a busy Airshow I went to a few weeks ago. [I got rid of the woman to the left]
I cannot speak more highly about this app. It runs great on my late 2008 iMac. Great buy.
The heal tool in Pixelmator seems to work the same or similar way to the repair tool in iPhoto. I wonder if this isn't a CoreImage function. A lot of what Pixelmator does is implementation of these OSX-native filters, which is probably why it works so well on older Mac hardware (runs fine on a late 2007 iMac too). My understanding is Adobe has never implemented CoreImage because it is only available on the Mac platform. I am prepared to brag on this a little if anyone asks me why I use a Mac.