Markus is a very kind host and has a great flat. He's very open to meeting people and having nice conversations, and I enjoyed hearing about his past travels and future plans.
The flat is well-kept, and is great for anyone looking for a place to stay that's accessible to the culture of Berlin. It's one block away from Hermannplatz, which gives you access to the U7 and U8 metro trains, as well as a few bus lines. Not to mention this neighbourhood in north Neukoln is bustling with many restaurant gems and parks.
Keep in mind that his flat is on the top floor, so you'll have to go up and down 6 flights of stairs. Additionaly, being on the top floor, if the weather is hot, the room will usually get more hot than a flat on, say, the 3rd floor. Neither of these were big issues for me, but they're things to be aware of.