This thread is getting out of hand.
Use what you are most comfortable with, or what your client is most comfortable with. Usability is mostly familiarity, and this extends to maintenance + development times for developers. If you have a lot of experience with drupal but none with wordpress, it will almost always be more efficient (both in terms of speed and best practice) to build with drupal. This is also vice versa.
There are very few concrete reasons why to choose one CMS over another as it all tends to be dogma based. Almost all of them sport similar features. At the end of the day all that matters is the opinions of your stakeholders. Exceptions to this are few and far between as all major CMS have enterprise level services available.
So basically, use what feels right!
Cheers,
Patrick