We stayed at Alan & Kasia StayBearlin's for four nights. Communication was smooth and hosts were very attentive and made sure that we have all things in place. Check-in and check-out was very easy and detailed instruction was sent by hosts in advance. It was very ideal to have two bedrooms for our group, a family of three and a friend. If you are planning to spend time inside there is not much place to feel causey except a dinning table in the kitchen. We visited Berlin in end of October and flat was very cold, because central heating will be on only when outside temperature is below 10 degrees (C), so take warm indoor clothes. Location was also good, near by tram stop, restaurants, coffee shops, bakery and lovely bike shop across the street :)
And our three years old son loved the popcorn machine.