I'm a working professional in Hong Kong and rented Mark's place to host a visiting friend. Mark has several units on the same floor, decorated similarly.
Mark is extremely responsive. He usually replies right away on Airbnb. The units are also clean, well furnished, and nice. I think for the money, these units, while small, are a great choice.
There are a few things to be careful of. First is the smell of sewage. It seemed that the toilet or shower drainage is backed up and the smell enters the room. Because the toilet is open and only two paces from the bed, it's hard to avoid.
Second, I rented unit #2, and the pictures showed a different unit. While similar, my unit seems even smaller than the already small units in the photos.
I can give a sense of the size to be more objective. Once I enter the door, there's a double bed on the left. The edge of the bed begins immediately at the door frame and ends against the wall, so the width of the room is (door + width of double bed).
As for the length of the room, it is roughly the length of the double bed plus a small table. There's also a cabinet that lines the back wall, I reckon it's about length of bed + 4-5ft.
A very slender bathroom borders one side of the room, it is the width of a toilet.
Having lived in hk for quite a few years, the unit is small even for me. However, I need to stress that if you are not spending much time in the room, which you shouldn't if you are traveling, then it is a great place for a good night's sleep.
Also, the corridor to the room and the elevator and outside of the building are considerably more rundown and dirty than the inside of the units. These areas are not shown in the photos.
All in all, I would choose Mark's place again, as the location is convenient, and the room clean. I think for the money it's a great choice for anyone visiting, and it's situated in an up and coming area that is close to good eateries and shops.