Pros
If it's your first start-up, then you will love it for the first few months. Typical things like unlimited drinks, beers, relaxed start time, fun young colleagues, crazy parties....all this and more. Great place to make friends if you are new to the country/Hamburg...most people are foreigners (maybe no German is crazy enough to work here).
Cons
Too many to list. The company is so poorly managed, at every levels. Lies are rampant. Promises never kept. People fired without reason and without notice. Poor communication - you find out your colleague have been fired via gossip. Company is totally paranoid about protecting their own privacy when they care so little about customer privacy . Totally ridiculous business goals, unachievable bonuses/targets, extremely unprofessional and angry public criticism from C levels if you don't meet their deadlines - everything is always due "yesterday". Some of the HR people are so unprofessional you could write a book on what NOT to do. Company takes total advantage of trainees and interns, expecting us to work 12 hour days on tiny wages. Trainees do the work of senior staff without recognition. So many politics it hurts your brain after a while.