We had a great time staying in Ryota’s.
The location is superb - 3 mins walk to metro station, Lawson convenience store. There’s Isetan and Marui dept stores 1 stop away, and only 2 stops away from Shinjuku main station.
The apartment is cleaned, and well equiped with amenities, including kitchen utensils (although we didn’t cook).
Perhaps the only downside was that it’s on the third floor without elevator - gotta keep in mind if you are travelling with many luggages.
If you could live with that, this is a great place to stay near Shinjuku for a big group