TLDR; 4/5 Basic Apt. Pros: great location, well managed (clear instructions everywhere), good size room, hardline home wifi Cons: beds were only okay - but the couch was ver comfortable.
Long Version: Overall, this place is really well managed and obviously done so by a group that manages many apts in the building. Everything is well stocked and well labeled for ease of use. The bathroom area was a little small, but otherwise the room is very spacious. They have both a pocket wifi as well as a home wifi!!! This is really unusual for most Japanese Airbnbs and very welcome (as many airbnb pocket wifi's can run out of data or get extremely slow with use from multiple tenants in a month). There's several 7-11's right around the corner, and there ikebukuro is a center for food and night life. There's also a donquixote on the other side of the station (nearer to sunshine city) that is open 24 hrs. It was a good place to pick up a cheap duffle bag for bringing back extra souvenirs! The building is pretty new and the apt well maintained (even have a vacuum cleaner in room for ease of cleaning up after yourself. They also put lots of extension plugs around for ease of charging phones and computers.
The apt has a washer with a dry function, but like most "washer & dryer in 1" units in japan, the dry function is not very good. In the end, we had to hang it up in the room and turn on the AC to "dry" or "heat" function.
The one semi-negative I would put on here is that I have back issues and the beds were not supportive. I think it is fine for the average person, but if you have any back issues (like me), it would be harder. In the end, I actually slept on the couch, which was much more supportive than the mattresses. But again, I think for the average person with no back issues, they may only notice moderate stiffness in the morning.
Overall, it was still a great apartment and very well managed. Anyone who likes ikebukuro area would love this apt.