Great apartment with everything close by, you can walk everywhere. Apartment is better than we had hoped for, will recommend it!
We had little problem with check-in, the mail with instructions has landed in my spambox, saw it 3 days after i have returned home. It was sent by someone else than Katarina, maybe thats the reason it mark the mail as spam. When we arrived, i tried calling the number but it didn't pick up, when i finally got someone, apparently the battery of the phone died out, after that everything went perfectly.
If you check in after 6pm, you should have a mail with instruction before you arrive in Berlin. If dont, check your spambox :) It can save you a lot of time and stress.