I don't think BDD scales well with complex requirements, the end result gets quite messy in my opinion, here is an example [1]. xUnit tests usually have a method per test, much easy to reason about. Not to put you off, just that has been my experience and I usually try and steer people away from BDD test frameworks
While I agree that BDD doesn't scale well I don't understand how xUnit (which is a unit tests framework hacked into BDD if I understand correctly) can help with that ?
BDD is BDD regardless of the framework, you want to use the same syntax
