They are nice people, but somewhat unprofessional. The interview was alright and seemed fair, but after traveling 400 km for an interview I hadn't even applied for (they had messaged me on LinkedIn), I didn't even get feedback or any kind of response. They also promised to cover my travel expenses of more than 100 € (long range train with return near midnight, as the interview took quite long), but ended ignoring me, even after I posted them the train ticket. I could have gotten taxes back for the ticket, but this way I just paid money for nothing.
As I ended up getting a better job, I'm not even disappointed they didn't hire me, just annoyed by the devil-may-care attitude.
After all, just another unexperienced, sophomoric startup. Nice people, though.