I was in Berlin for an expo and I couldn't habe picked a better place to stay. The room, ensuite bathroom and kitchen were very clean and provided everything I needed. There is also a little porch which is great for sitting outdoors in summer. Distance to the expo is 20mins by foot or 8mins by car, 11€ by cab.
Communication beforehand was seemless - I never actually met Helena but she texted me on my first day to make sure everything was alright.
I shared the little appartment with another guest. However, she had her own room and bathroom as I did and we only shared the kitchen, so there is still lots of privacy if needed.