Paul and Jana were very welcoming. We didn't see them but they make sure that you are comfortable and that you like your stay in Berlin.
The location is very good. It was easy and fast to go around the city by public transportation.
Clean appartment and very stylish with enough towels and everything you need to clean your dishes and your clothes (they have a washing machine).
For vegans: There is a vegan grocery(Veganz) with only 10 min walking from the appartment. :)
Just a bit noisy(you can sometimes hear then walking upstairs) But it wasn't a big deal with us. Just bring some earplugs.
For what you pay it is a very good value!