I stayed in Falko's flat with my partner for two months. Overall it was a very good stay, and I'd recommend it to anyone considering staying in the area.
The flat was beautiful, and was very clean. The interior was very spacious, and It was extraordinarily well-equipped. The kitchen had everything we needed for cooking even complex meals. We were consistently impressed by how much thought Falko had put into making sure we had everything we needed.
The internet was a reliable 40Mbps when connected by Wi-Fi, and 100Mbps when connected via Ethernet cable. There were only one or two short outages (~two minutes long) throughout the whole two months.
The flat is a 10 minute walk from the closest station, which has a direct line to both the airport (25 minutes away) and Berlin city centre. There is a tram stop directly outside the front door that goes to the station, if you aren't a fan of walking.
The flat is in a pretty quiet Berlin suburb. There are a handful of restaurants, but don't expect much on that front. There is a great supermarket a few minutes walk away from the flat. The local residents speak very little English compared to somewhere closer to the centre.
All in all, we had a great time.