Great nest to base yourself in to explore Berlin. A bit cosy for 6 people- you really have to like each other. The only privacy really is the bathroom, so if you're the type to need space to hide away from your fellow travellers and recharge, it's not for you.
The shower is good, but the boiler is on the small side, so you'll have to have relatively short showers and give it time to warm up again before the next person uses it. We weren't in a huge rush to get out in the mornings, but we needed a good 2 hours for everyone to take shifts in the bathroom and allow enough hot water heating time for everyone.
Kitchen is small but has everything you need to make basic meals.
The heating is very good, there was plenty of bedding for everyone, it was comfortable and quiet. Thanks Martin for a lovely stay!