I had the option of moving to Berlin or finding something else, and whilst I liked some aspects of Berlin, eventually decided not to move there. Of course, everyone is different but the relevant points to the question are:

1) whilst it is cheap - and rent is included in that statement - it is also big and low density. I felt that I wouldn't want to live away from the central, fashionable areas as the rest of the city feels a bit deserted. Living there probably adds 500EUR/month to your costs.

2) most of the "entrepreneurial" action seems to be in the arts. I didn't see lots of technology and/or international companies e.g. if things don't work out for you.

I have a friend from Berlin running a technoloogy company who loves it there though - and he seems to be able to hire a reasonable amount of talent. And some people don't mind the commute/quiet life as much as me.