Karsten's flat is an exceptionally stylish - in a Berlin way - one bedroom flat in Mitte. The flat is clean, check-in was simple and near both the main tourist attractions - such as museum island - and the U-bahn. Also, Karsten was clearly an experienced and attentive host as he responded quickly to any queries we had. Overall, as you can probably tell from the tone of this review, I would highly recommend staying in his flat if you are looking for somewhere to stay in Berlin; especially, considering that other flats/hosts I have stayed with in the city are nowhere near as good.