If you get the chance, stay with Maria! Her apartment is lovely, the room is great, and Maria is a wonderful host. She is helpful, kind and considerate and very friendly. I wouldn't hesitate recommending her or her apartment. If you're an English speaker then it's great because her English is very good.
It's about a 6-7 minute walk to the S bahn and from there you can get to all the attractions in Berlin within 20 minutes.
Thanks Maria for your help and making my German experience even better!
Vielen Dank!!