I maintain the Eloqua module on Drupal.org: Eloqua | drupal.org
This module offers webform integration and page tracking with no custom coding required. There is also the Eloqua API (Eloqua API | drupal.org) module which allows you to integrate with any Drupal form, although that requires custom code to integrate.
Our shop Mediacurrent does Drupal-only development so I am biased towards Drupal myself.
