Booked this apartment and was not really sure what to expect as it was fairly cheap and there was only one trip advisor review but was pleasantly suprised when we arrived.
The apartment is very clean, modern and spacious which are the basics you really need to go exploring also had kitchen facilities which were handy to be able to prepare food with a Kaiser market which was close by and open until fairly late.
The apartment is not exactly central Berlin it is close to a tram which takes you directly to Mittre and the main sites of berlin. also a short walk to the U-bahn making it fairly easy to access other attractions. the public transport system is really easy to navigate. Getting to the apartment from Schonefeld aiport was also very straight forward.
The apartment was all in all a great base to explore Berlin if you want a cheap and nice place that's a little bit out of central berlin would recommend a stay here.