We stayed in two neighborhoods in Berlin for a 10 day trip: Kreuzberg and Prenzlauer Berg. These are always on the top list for hippest parts of the city. Kreuzberg was just ok. The highlights are some of the best restaurants like Sfizy Veg, Brammibal's Donuts and No Milk Today. Some of these are in the neighboring area Neukoln. It was a run-down area before because it was at the border of the wall. After the wall fell, the best techno clubs and artists moved in. Prenzlauer Berg is a much better neighborhood IMHO because it's more central, has better food and coffee. The area is Germany's number one fertile neighborhood, so kids and families are everywhere. I've heard the streets of Prenzlauer Berg as the "Stroller Autobahn" and it's true.
My first impression of Berlin was just shock. It's so different than every other European city I've seen. Because of WWII and the DDR, the city was completely re-built. It's the newest old city because mostly everything has been built after the 1950's...even the beautiful Tiergarten park. There are so many stats that come from Berlin: #1 vegan city in Europe, #1 green city in Europe, #1 start-up funding in Europe. It's an oddly perfect city for us. We love parks, vegan foodz, and tech. It has 25% non-Germans, so it's full of expats and English speakers. I met a lot of people who packed-up and moved to Berlin including many Canadians and people all over Europe.
The best part of Berlin is just riding your bike through the windy streets, stopping by to get some vegan dumplings and Momos or some vegan donuts from Brammibal's and laying down in a beautiful park with birds chirping everywhere like Tiergarten...while drinking ChariTea Sparkling Mate our favorite drink.
We went to a bunch of meetups because the vegans and techys are thriving there. First, there was Romy's amazing Secret Vegan Dining meetup where she cooks an amazing 3-course meal with drinks and desserts at her house. Next, we went to the monthly vegan brunch meetup at Kopps (best all-you-can-eat vegan brunch in the world for 15 euro). During the week, we went to a barcamp style meetup at Wikimedia called the Social Digital Innovation meetup. The next day was an IOT meetup with a panel of three German start-ups and the craziest pretzel spread you've ever seen. Finally, we went to the C-Base hackerspace for a Crypto-party night...in a crash-landed spaceship that lives beneath the entire city :)
Berlin is a pretty bad place to visit if you're looking for tourist attractions. There is Checkpoint Charlie that will entertain you for 1 minute. There is the Brandenburg Gate which is beautiful. There are many memorials for the horrific history and there is Parliament. There are probably a few more things, but Berlin has no f-ing Eiffel Tower. It's just a crazy city that was rebuilt after the fall of the wall and re-invented itself in the last 28 years.
This is not the old Germany that people think it is. People told me Germans are cold. Germans only eat sausages and I'll die of starvation. None of that's true of course, and the country is really diverse. Berlin doesn't even care about the Bavarian pretzels and beer, so there you go.
Germans were so nice to us and Berlin was so young and thriving, I kept forgetting I was in Germany. I was surprised multiple times when I heard people speaking German because I thought I was at home. I thought it was Los Angeles. This is a place I would live in or visit more often, so my advice is to definitely travel here.