I know these types of drupal vs. wordpress maintenance questions have been asked before but I want to hear from a different audience than most other posts and have a true interest in peoples responses.
Two important points before you consider responding:
1) Please if you respond provide a link (or links) to a larger complex drupal site that you have maintained through at least 1 full point upgrade of drupal (i.e. 4->5, 5->6, etc.). Your opinions otherwise are not based on real life experience and the web is full of answers from those viewpoints.
2) This is not a wordpress vs. drupal debate or any such thing. Personally, I find Drupal very useful but painful to keep current - I am curious of other folks who run (again large and complex sites - include links) in other systems and their experiences overall with the rate of plugin updates, core updates breaking the site, core updates breaking plugins, etc.
And before someone says it large and complex is indeed relative - I'm speaking of sites that are not just blogs, not just brochures, but that have active forums, customized user experiences/profiles, fair amount of content, perhaps multiple authors, social media aspects, etc.
Please only people who have real-life experiences (verifiable) respond.