Frank's place is great and we had a wonderful time. It's a beautiful flat in a lovely area of Berlin, very easy to get to from the station, good public transport links and with tons of shops and restaurants in the area itself. The flat is spacious, airy and clean, with everything we needed and lots of local information. Check-in went smoothly and communication was really easy and quick. There is one big and very cosy bedroom, and a decent sofa bed in the living room (I didn't find the sofa bed very easy to sleep on, which would be my one tiny difficulty, but my friend had no worries at all and slept really well). I'd highly recommend Frank's apartment to anyone visiting Berlin!