Excellent apartment and much bigger than presented in the photos. The decoration was perfect and the space was brilliant to spend time in. I stayed for a couple of weeks to enjoy a little Berlin, while working with my girlfriend, from the apartment. There's ample space for two people to work from laptops and the internet is likely the fastest I've ever seen in an AirBnB.
Friedrichshain is, as ever, an incredible area to spend time in - with brilliant restaurants and a lively culture. Travel to various other parts of Berlin is fairly simple with the U-Bahn, however it's of course not as connected as some areas. You can usually get pretty much anywhere within the AB zones within about 25 minutes.
One word of warning - during our stay in July 2019, there was some significant building work going on in the supermarket downstairs which started early each morning. Over the last few days, there was also some roadworks outside which added to the noise. It will likely wrap up fairly quickly, but this could be a factor in your choice. Please speak to the host as they will be able to let you know if it has now concluded!