Martina & Charlotte's place was awesome. The location was surprisingly close to a lot of cool places (even when we wanted doner at 4am, it was only a short walk away!). It was in a cute little area with bars and restaurants right next door. We took ubers most places (ie: sights and clubs) but the one time we used the bus system it was super easy to navigate. Everything is delightfully cheap in Berlin compared to the US (beers are around $4 and so is a full sushi roll) and almost everyone spoke English so it was not hard to get by.
The hosts were quick to respond and answer any questions we had. Charlotte met us for the check-in and gave us suggestions on where to eat and drink. We did not cook in the apartment but if you're planning on it just know the fridge is small (like in a dorm room). The place was super clean with good lighting and the bathroom was spacious enough for two people to get ready. I would absolutely recommend it!