My wife and I had an enjoyable 9 nights in Claudia's place. We arrived early so Claudia sent her cleaner with the keys to let us into the Smithy. The place is airy and bright during the day with a nice homely feel to it. Everything is clean and functional and the central heating was nice to come home to as Berlin was a bit chilly. There were no instructions in the Smithy, however Claudia was on hand to answer any questions we had. There is a computer upstairs for guests to use which was very convenient. There is no lounge as such, however there are a large and small dining table to eat at. The TV is small but we tend to watch movies etc on our laptop when travelling so we didn't use it. 2 bathrooms, 1 double bed, 1 king size and a sofa bed.
The local area is fairly residential with a few bars and cafes on Potsdammerstrasse, we found a cozy pub (Joseph Roth) opposite the corner of the street the Smithy is on, the beir is great and the schnitzel is tasty (weekdays only). There is a bar just outside the block the Smithy is in. The Thai restaurant (Edd's) next door is good also, the red curry duck is great. There is a Rewe supermarket about 3 blocks up PotsdamerS, which has everything one needs.
Potsdamer Platz & Sony center are a 15 minute walk with 2 art galleries on the way. The nearest U-bahn station (Kurfurstenstrasse) is 2 blocks away on the U1 line, from here you can connect to other lines to take you where you need to go and its so easy to use compared to other cities.
A few times we just got a taxi back from the center (Freidrichstrasse-Mitte) after a show and dinner which was 10-12 euros. The main shopping area where you will find KeDeWe is only 2 stops on the U1 line at WittenbergPlatz, and the longest remaining part of the wall (Eastside Gallery) is accessible from the U1 line in the opposite direction at Schlesisches Tor.
We would recommend staying here if you are looking for a cozy place away from the center but close enough to the action.