I definitely recommend Rei's place! I had a pleasant one-month stay here. This fully-equipped, well-designed, and clean apartment is located in a quiet area. In its neighborhood, there are a lot of cafes and restaurants to explore. If you need anything, you can easily go to bigger stations such as Tachikawa or Shinjuku. Furthermore, Rei is a great host. She is responsive, flexible, and kind.
One thing you may want to consider in advance is Wi-Fi. It seems slower at night so you may want to rent Wifi routers if you have many online meetings at night. However, in other cases, Wi-Fi will not be a huge problem.
Overall, I strongly recommend Rei's place if you plan to stay in Kunitachi.