Hands down, after my simple installation tests, Drupal is more portable. No? Oh really?
Try renaming your wordpress directory and see if wordpress will automatically figure it out... lol No, it won't. Drupal will.
Simply because Wordpress developers have or perhaps had poor programming standards believe it or not. It is pathetic when you think about it because programmers should always take this into consideration when programming. This is why Wordpress will cost you more in the long run. While it will offer you features, when something breaks, you better believe its going to cost you more money.