Our group of 6 (two seniors and 4 adults aged 28-35) had a very lovely time.
Check in was simple with a key safe and clear instructions given with a few days notice. We also were able to leave our luggage on our last day to allow us to continue exploring Berlin
The kitchen had all utensils you could need, and the living area, bedrooms and bathrooms were as spacious as I've seen.
Easy to get to the U-Bahn and there's restaurants and grocery stores within 5-10mins walking distance which is perfect.
Only negatives would be the pillows are a bit soft (personal preference) and there was no shampoo or soap
Otherwise it was a perfect stay!