We enjoyed our 6 nights here.
Pros:
The place is very clean
Close to Shinjuku station
A lot of convenience stores, shops, restaurants nearby
Friendly staff & fast communication
Note, if you're travelling with suitcases, a wife, and a baby with stroller, it'll probable take you longer to walk from Shinjuku east to the apartment the first time. There's a nice restaurant just before you get to the 7-eleven on your right (B1) called Tofuro (I believe), and the building across the main road from the Yoshinoya has a great ramen noodle shop (Ippudo).