Overall the flat and host were both excellent. I would definitely recommend staying here.
My girlfriend and I booked this flat months in advance for a spring trip to Germany and we couldn't have asked for a better experience. From the get go Andre was very timely with communication. He even helped arrange it so that we could check-in early, which was a big help.
Once we got there we found a large and inviting flat, complete with all the amenities (electric fireplace included!) you could ask for. Andre gave us a few suggestions on places to go in the area and we were off.
The flat is, as mentioned, extremely close to an U-Bahn Station and there is an S-Bahn Station not too far south. It's right in the middle of Neukölln which offers tons to do during the day and night. It's also just a quick U-Bahn ride to central Berlin.
The furnishings are all very comfortable and we didn't need to provide anything in the way of linens. The space also gets TONS of light, which was a welcome surprise.
A last note is that I was looking for a gift for my mother - a spice mix for Glühwein. When we couldn't find it I reached out to Andre to see if he knew where we might get it. He told us that it was out of season so we'd probably have a hard time getting it. Instead he made us a whole batch of the mix himself to bring home with us.