Test database isolation with Behat 3, Doctrine 2 and Symfony 2

I am introducing functional behat tests on a Symfony2/Doctrine2 application and am deciding how to handle database isolation and data fixtures.

Are there any pitfalls to setting up a separate test environment with its own completely separate mysql database that gets populated by a dump import prior to execution of the behat test suite, and then emptied after suite execution? I'm trying to avoid using data fixtures unless I really need so as to save the time of manually writing foreign key relations and what not.

Any guidance is appreciated.