Me and my boyfriend visited Berlin for 5 nights and Karstens apartment was the best choice for us! He was so helpful and patient when we were booking and really flexible with our check in time! It was so easy to find and Karsten gave us a detailed description of how to get there. Once we arrived he was welcoming and took the time to recommend some great places to eat and drink. The apartment is close to the underground so it's really easy to get anywhere in the city without being in a noisy and busy street! The apartment itself is lovely and spacious and very modern; and so reasonable compared to many similar places in Berlin!
We had a wonderful time and couldn't recommend it enough!
Even if the places you're looking to visit aren't that close, Karstens apartment is a great place to stay in Berlin!