I found a bug somewhere along the lines of using Gravity Forms with Mandrill. I'm using Gravity Forms 1.7.2 and in my form if I enter an email in the BCC field under notifications those emails don't get sent to. That's with using the wpMandrill plugin.
I also have Event Espresso installed and was previously using the "EE Email Transactions Plugin by Event Espresso" plugin which worked fine before the newer Gravity Forms was released. When using this plugin and adding an email to the BCC field under notifications the form fails to submit and a server error is displayed.
I'm not sure where along the line its having the issue if its with Gravity Forms or with Mandrill but I'm posting this here as well.