The apartment was great - just as described. Good location, close to the best falafel in town (and a major transportation hub), quite central. The mattress was a bit too soft for my preference, but that's just purely personal - I'm used to sleeping on very hard ones.
All in all, a great and very clean place with very clear instructions on how to use it. Also, outstanding and timely communication by owners. If you're going to Berlin for a longer trip, I'd definitely recommend this listing.