We stayed for seven nights at Annetts place with our children (one is two years the other eight months old). For us it was perfect because there was a highchair for babys as well as some toys and books. There is enough space to move around. The street is very silent but still it doesnt take long to go to busy/interesting places like Warschauer Strasse or Kreuzberg and by tram its easy to go to Prenzlauer Berg.
The flat is a real Berliner flat with high ceilings and wooden floor. I would always come back especially with the kids.