I spent 6 weeks at Mo's for a language stay and everything was perfect, I really had a lot of fun. The apartment is very comfortable, clean and welcoming. You have everything you need to have a great stay.
The apartment is very well located between Mitte and Kreuzberg, everything is close by public transport. The area is quiet.
Mo is a very kind and attentive host. She is always available to fix any little problem (for example: my bed was broken and the day after I had a new bed). She responds quickly to messages which is very helpful to get any sort of informations. I came to learn German and she was willing to help me progress. She has a little girl who is adorable.
I recommend this place to everyone, you can go there with your eyes closed. I will return without hesitation.