We were 3 friends and Marley's place was simply perfect for us. There was not any problem with the check-in and check-out was also flexible. The beds were comfy and clean as well as the bathroom and the kitchen. It made us feel really great when the apartment had a verticle bathtub since we were 3 men! The only suggestion I can make is to increase the piece of glassware and tableware in the kitchen and maybe some essentials can be included in the fridge. But that does not even sound a disadvantage since the street has so many shops to fulfill what is needed.
The first best thing about the apartment is that it is just next to the metro station. It takes not more than 3 minutes to be on board for U-Bahn which is perfect for transporting to the city centre!
The second best thing is the balcony as well. It is not so big but it is enough to have a fresh air in the morning with the smell of Berlin streets!