CRM for drupal

I’m looking for a CRM that could fit properly in my new project. It’s a Drupal web based on a bussines company (real state agency and bussines trading).

I’ve been collecting some info in a few sites, some of them say that CiviCRM is the best one, some others just talk about redhen…. Can’t really find any significant differences between them, so I would really appreciate any help or opinion about this.

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