I stayed at Inn Square for 5 weeks. The room is small (as to be expected for this price range in Hong Kong) and generally well kept. They clean your room once a week and will replace your towels then.
The overall room condition is good. The place is quite minimalist which makes it easy to keep clean. The toilet is not as small as the pictures look and the shower water pressure and heater is very good. The bed is a large single bed which is relatively firm/hard. There are a good number of wall plugs and you have a small protrusion which can be used as a table in a pinch (that being said I did most of my work on my laptop whilst on my bed). There are a lot of little pockets, storage spaces and hangers to keep your clothes and other knick knacks.
Location is decent. It is next to Austin MTR which brings you to East Tsim Tsa Tsui. A lot of good food in the area and there are a LOT of laundromats and laundry services which were absolutely essential for me as I needed to wash and iron my clothes.
A few bad points; the walls are quite thick but not thick enough to keep out the noise from other rooms altogether. If you are a particularly light sleeper it may annoy you. There are no windows which means that you don't get natural sunlight; this also means that it is near impossible to dry your clothes in the room, and puddles or damp spots do not evaporate.