Salesforce is an awesome CRM application. And the first ten licenses for Salesforce for Nonprofits are free. It's a great offer but isn't always the right solution for a nonprofit.
Salesforce is successfully used by the biggest non-profits but smaller organizations can struggle with the need for consultants to implement common requirements. CiviCRM along with Drupal provide more extensive "out of the box" capabilties for non-profits. Also, the CiviCRM data model has been developed specifically for non-profits and can be more intuitive even for some fairly complex requirements.
Last, but perhaps most importantly, if your goal is to integrate your data management with a website, CiviCRM and Drupal provide unmatched capabilities that do not require custom coding or API based integration. A demonstration of these features is an eye-opening experience.
Nubay has worked with clients that have started with Salesforce and needed another solution. We'd be happy to discuss your experience and answer any questions.