While concrete5 was in the running for some more categories (one of which was "Best Open Source CMS" too), it only won in the "Best CMS for Designer" category.
But it's pretty obvious it won this award, as designers can do pretty much EVERYTHING they want on their pages. No specific fields they need to fill in, but drag and drop blocks on places you want and places you like.
Make sure you vote for your favourites next time the awards will take place, starting somewhere December. For more information, go to http://www.cmscritic.com/.