Never ending interview-rounds with promises that they will get back with feedbacks which everytime happend but never, never, never on the given deadlines. It was painful. I got the impression that they are so unserios. But no wonder- well known startup mentality. They were not able to explain what exactly the job responsibilites will be. It was also curios that the position it was a team lead one but not entailing the requested title... Lots of wierd things. And I rejected the collaboration.