This place isn't cheap, but it's Tokyo. If you can find a cheap place to stay something's wrong with it! :-)
Great location. Practically on top of the E/F subway station -- one stop from Shinjuku station. There is also a Lawsons between the apt and subway station making it super convenient to pick up snacks and drinks. There are many great attractions within an hour walk. I would recommend walking as much as possible, to really get a feel for the city.
The apartment was nice and clean. There's a fire station not too far away, so you'll hear sirens, but from the 8th floor it's distant enough to not be a bother.
The water pressure is outstanding and there is endless hot water if you want a long shower. The apt is actually a part of a hotel with service downstairs. You'll get fresh towels every day, water bottles, tea bags, etc.
The apartment has two rooms, of sorts. One room is small and is for sleeping on the floor mats. The other room has two twin beds. However, the "bedroom" is around a corner from the bathroom, but doesn't have a door. So if you're sharing the apt with friends/family privacy will be problematic.
My wife and I took her parents on the trip. They got the bedroom while we slept on the floor in the other room. It was comfortable enough, but we had to be very, very, quite. ('nuff said.)