Howy's flat was clean and exactly as pictured. It wasn't luxurious, but the listing was very accurate, and I didn't intend to stay inside all day anyway. The flat had everything I needed, and was well worth the affordable price. It was up one flight of stairs, so take note of this if you have any mobility problems. I had multiple last-minute changes to my travel plans and arrival time, but Howy was completely flexible and able to meet me for check-in quite late at night without any problem. He was very quick to respond to texts.
The immediate neighborhood is charming and safe, with both posh and cheap eating options and lots of shopping, and there is access to two different tube lines (about 5 minutes walking time in one direction, and 10 minutes in the other). If you're in Berlin, don't limit yourself to a hotel in the middle of the city! You'll have a much richer experience if you stay in one of the more fun neighborhoods and explore the shops, galleries, and street art, and for a cheap multi-day ticket, you will still be able to take public transit to see the Wall and all the other main attractions.
I would recommend this listing without hesitation to anyone who wants to find an affordable but nice base point for exploring this wonderful city.