The place is on a 10 minutes walk from Shinjuku Higashi Metro station. There's a Thai straight next to it and a nice Japanese restaurant (recommend it) across the road. There is also a Karaoke bar at the ground floor, but we did not hear any noise from it. There is plenty of watsons and 7/11 around, but for more restaurants you have to walk 10-15 mins.
The apartment is nice and clean. The kitchen had almost everything we needed; kettle, pans, cutleries, fridge etc. Just a toaster would have made it complete, but for the rest most is there.
The apartment is doable with 4, however it might be a bit small (like al Tokyo apartments btw). We enjoyed our stay and would recommend it for others as well