Great place! Stayed there with a few friends of mine in August.
Check in was smooth. We were travelling from the US and had been in a couple European countries before that, so we were tied to a schedule. Catharina was really nice to give us the option to leave our stuff at the apartment before check in time (we ended up arriving there after check in time so it worked well).
The apartment is really cute, well decorated, super clean, and it's in such a great location. It's in a courtyard of a building so it feels private. It's a 5 min walk from the S Bahn train, which you can take straight to central Berlin (12 stops or something like that to central station). There are a bunch of groceries store and clothing stores really close to it, as well as several bars and restaurants. The town across the river is a 15-20 min walk, and was really nice to walk around.
It's a great place if you're looking to be close enough to central Berlin, yet far enough to enjoy its suburbs.