I stayed for 3 weeks both times. To be honest, I did look around for other apartments that may be "closer" to touristy things like Alexander Platz and Unter den Linden etc. But, in all honesty I just can't get past the fact that the location and proximity to the U Bahn, S Bahn, Bus routes, stores like LIDL, Woolworths, and Aldi, as well as various restaurants is just way too convenient. You are only minutes away from anything you want to see by using the public transit system.
I gave it 4 stars this time only because there were a few issues with the lights/circuit breaker on 4 occasions and with the WIFI going out a couple of times. BUT to be fair, the landlord was quick to respond and got things squared away ASAP. My other complaint is that there are not many channels on the TV nor is there a microwave but, this is obviously not a deal breaker for me. The apartment is exactly as it seems in the pictures and the kitchen is well equipped for the most part. I did buy a few cooking utensils at the Woolworths (very inexpensive) to supplement what was there. Also, it would be nice if they made 2 or 3 fans accessible during ones stay in the non-winter months (I bought an inexpensive fan and gave it to my German language teacher). One last thing is that it seems to be close to an ambulance station so you will hear sirens from time to time, but again not a deal breaker for me.
After much consideration and looking around at other apartments, this will probably be the place I stay every time I go to Berlin; the only thing that would make me rethink staying here would be if the price was too high. I highly recommend staying here.
I only have a couple of minor issues. One is it is close to a major steeet so emergency vehicles can be heard from time to time. The other minor things are a microwave and fans would be nice. Even with that I will absolutely stay here again when I return. The access to public transit is perfect, the U-Bahn is right arohnd the corner and the S-Bahn is just down the street. There are plenty of shops close buy as well as grocery shopping. The kitchen is well equiped and the apartment itself was very nice, exactly what is in the pictures.