Recently I met with a Senior Vice President of Strategy and Innovation at a large well-known non-profit who is planning to launch a major initiative and he’d narrowed his choices of platform down to two (2): Drupal or WordPress. On a personal level we hit if off fabulously so if it were just personalities I think he might be inclined to take my recommendation on faith but I sensed he is enough of a real professional that he looks beyond the personality of the advocates to assess the actual best solution for this organization.
Rails running on Matz's Ruby Interpreter (the de facto reference interpreter for Ruby) had been criticized for issues with scalability.  These critics often mentioned various Twitter outages in 2007 and 2008, which spurred Twitter's partial transition to Scala (which runs on the Java Virtual Machine ) for their queueing system and other middleware .   The user interface aspects of the site continued to run Ruby on Rails  until 2011 when it was replaced due to concerns over performance