Personally I like the Drupal themes a lot more. A the time of writing, I am running a theme called darkmatter, that fits into the genesis framework, which in turn makes use of Drupal.
Installing themes in Drupal is as easy as in Wordpress. Simply extract the .tar.gz into the sites/all/themes directory and you are set. This theme was SLIGHTLY more difficult to install, as I first had to install the genesis framework - which is actually just installing the genesis theme....