Aileen's place is the best room for 2 person. The building has elevator that might convenient for travelers with big luggage. The room has everything you need while you travel (Netflix, tea, iron, hairdryer, fast wifi). Also i appreciate the chocolate and flowers as the personal welcome gift. The heater, washing machine and dryer are mostly in Japanese but Aileen provide nice clear guidance book so worry not.
In term of location it is exactly like described, 6 minutes walking from Nakano station but along your walk to and from the station you'll find restaurants and convenient store like Family Mart. Nakano is very close to Shinjuku, 1 station away if you use Chuo line but 3 stations away if you use Chuo-sobu line.
Overall do not hesitate to book Aileen's place, if i return to Tokyo i will definitely stay again in this place. Cheers