Not at all. We have tweaked the various settings of PHP, Memcached, MySQL, and so on to be optimised for Drupal, and we have common configurations in place for Nginx and Varnish to run Drupal websites, but under the hood our stack is a standard drop-in replacement for LAMP.
Among the other PHP applications we help clients to run are:
While we specialise in Drupal, we're happy to help to run most other PHP applications. If you're happy to take some responsibility for the app config, we can usually run it, and keep it running.