We loved the large bedroom, very light and airy. The kitchen was also good and we had some lovely breakfasts chilling out in there. The bathroom is very small, but is well arranged and we didn't find this a problem.
The location is good, maybe 8 minutes to walk to the nearest tube, but there is plenty nearby, including the canal and some interesting Kreuzberg streets. There were buses running closer to the flat, although we didn't use them. There are 2 supermarkets very close by, which was handy.
We didn't end up meeting Erez in person, but he provided full details on how to check in, which went smoothly. He was also flexible about letting us leave our bags in the flat until our evening flight home, which was much appreciated.
Note that there didn't appear to be a mirror in the apartment other than above the washbasin, so be prepared.