Friedrichshain is a recommended area to stay in, it is edgy and punky (lots of interesting graffiti and artwork on buildings) and Ulrike Und Kai's place is in a perfect location so don't hesitate to stay. There's a variety of restaurants from different cuisines within walking distance from the apartment (Cho Dong - Vietnamese place 2 mins walk away was super tasty!), cool and hip cafe's and even better for convenience you have the Penny supermarket right across the road! The main train station Berlin Ostkreuz is an 8 min walk away and directly connects to the Schonefeld airport.
The apartment was clean, a spacious layout and very simple inside which was nice. The main bedroom was very big and the living area where my friend slept on the sofa bed was just as large. We did have to clean the sofa bed up a bit before putting the bedding on as there was lots of crumbs stuck in the sides however no issues with the main bedroom.
The kitchen has all the amenities you need for a short stay however I couldn't find a flat pan..not sure if it was in another cupboard. The bathroom is lovely, nice powerful shower and a washing machine. I have to say the heating system is brilliant especially as we visited in December, you can control the heating and it is very quick to heat up the place, so we didn't freeze at all. The Wi-fi connection is good too!
Our only gripe, although minor was that we couldn't find a hairdryer and after contacting the host she did confirm that there was not one. So, we had bought one from the local store to use for the 5 days which should now be in the apartment for everyone to use :)
All in all, we had a lovely stay as it was comfortable, safe and good value. Thank you.