Our family of 4 (2A/2C) stayed at Ken's place and it was very comfortable. It is actually bigger than it looks in the photographs. The space is clean, neat and functional.
It is in an excellent location. In a quiet spot but an easy 10 minute walk to Akihabara station and electric town. Also a reasonably easy walk (1300 metres) to Ueno station (JR East Shinkansen if you don't want to go to Tokyo Station).
The double beds are big for Japanese standards and can easily accommodate a couple. One of them is a little hard by western standards but this is a personnel preference. Bathroom and shower room is a good size. Heating worked well and there was always sufficient hot water.
Although the apartment is on the 3F (2nd floor for British/Australians) we had no issue with access with our luggage.
I would certainly recommend staying at Ken's place while in Akihabara.