On the 'fake it,till you make it' path,Berlin seems to be right in the 'fake it' part.You guys write about low costs of living,however there are cheaper places in Eastern Europe with better tech talent availability overall.You mention the nightlife and a couple of the clubs are indeed world class,but I'd doubt it that you go there more than 5 times a year.The internet in Germany is borderline third world quality,in Bulgaria and Romania you get some of the fastest internet in the world for a fraction of the price you'd pay in Germany.The women are better than in the UK,but far from the best looking in the world.
What I'm trying to say with this point is,I don't really see the advantage of being in Berlin in the early stages of your business too,when you're just a 3 people shop,busting your asses all day to move things forward
Having written all that,I loved Berlin during my few months stay.