A nice place in a good location, close to the hip Kreuzberg. We stayed with four people, and it was convenient. There's actually a double bed in the living room now, instead of a sofabed. I liked that the place was nicely decorated, and not just bare bones. It really felt like a home, and not just a place with the basic minimum. I never met Ina, but communication (by mail) was good, and the check-in procedure was clear.
Just getting there on a Sunday by public transport was a bit tricky. The 147 bus apparently doesn't go on Sundays. If you don't have too heavy luggage, walking from the S or U Bahn stop (a bit further away) should be okay. Leaving was fine. The 147 bus stop is just a few steps away.