The apartment in Mitte is in a sensational location & wonderfully spacious, perfect for 4 people.
All the best Berlin sights are in walking distance & there's plenty of shops, restaurants, cafes, supermarkets, chemists & a main train station nearby.
Arrival & departure were easy & Dagmar (the housekeeper) was friendly & helpful. Beds were comfortable, kitchen was well equipped & functional (we cooked a few breakfasts & brewed lots of coffee in the percolator), the wifi worked perfectly & the lounge is a great room to hang out in after a long day of sightseeing (big TV & large, snuggly couches with plenty of cushions & rugs).
The neighborhood felt safe & the apartment was secure.
You can even hire bicycles from the hotel around the corner, lovely for riding around the Tiergarten (don't miss the beer gardens tucked away in there).
The apartment is 5 minutes walk to a whole bunch of museums & galleries & we visited a few... I particularly enjoyed the German History Museum, filled with amazing historical stories from the last 2000 years, artifacts, paintings & some very moving exhibits on WW2, the communist era & the reunification.
Berlin is a remarkable city that's both poignantly old & refreshingly new. The Mitte apartment is so very Berlin & staying here perfected the authenticity of our Berlin experience. Great value for 2 couples. We loved it & recommend unreservedly.