This apartment is a complete gem and I loved the time I spent there. First the location is superb. It is in the heart of Mitte - a fantastic location full of restaurants, bars, cafes, shops and cinemas and a short walk from Museum Island and the River Spree. It also has incredible public transport links - 3 underground stations within 10 mins walk, an overland train, the tram and buses. Then there is the flat itself, which is just lovely. Located on the 7th floor, it has panoramic views out of every window and is flooded with natural light, which for me is incredibly important. To the front is all the hustle and bustle of the city, and to the rear you have the feeling of a local neighbourhood, where you can sit on the balcony and hear church bells and children in the playground. The apartment building itself is not glamorous, and in need of some redecoration, but as soon as you enter the apartment itself your spirits rise! It just has a lovely atmosphere. The beds were very comfortable, the water hot and plentiful and I loved the fact I could have a bath or shower. So many apartments in Germany have showers only.
Just one thing to be aware of: If you have problems with steps it isn't suitable, as the lift goes to the 6th floor and so you have to walk up 2 flights of steps to get to the apartment itself. Not a problem for me (except when I arrived with a huge suitcase) but could be for others.
I didn't meet the hosts as they were away, but we communicated before, during and after my stay and they were friendly and flexible. A very nice neighbour checked me in and was very helpful when there was an issue with some lights. The flat was also spotless on arrival.
All in all I definitely recommend this apartment and it would certainly be my first port of call when I return to Berlin, which I certainly hope to do. Thank you very much, Tove and Julian.