Overall, G-Stays was a good place to stay in a fantastic location and I would recommend them. My stay was not perfect because there was construction ongoing the entire time that I was there from 8am-5pm. There were signs when I arrived indicating this, but the thing is, when you are on vacation, construction at 8am can easily wake you up and it did (it could be very loud at times). There was also white tarp all over the floors and my door was covered in plastic wrap. At one point, I was sitting in the bed during the day with the curtain just slightly open when a construction worker hopped over the side of my balcony onto the balcony and started doing some work. I did not get any notice about this, and I kept my curtains shut after this.
If not for the construction, I think I would have had a great stay, as the room was a good size for Tokyo and the guy at the front desk was always very responsive and nice.