In general my stay, which lasted for around 40 days, was endurable.
My private room was good (although the cleaning service obviously just changed the bed clothing and collected the trash. I understand more for "cleaning" service.)
Our bathroom (shared with one other tenant) was kind of dusty and dirty (but I am also really fussy when it comes to hygiene and cleaning in bathroom and kitchen).
Without a washing machine nor a real kitchen, I think it is really inconvenient and expensive for long-term stay.
Further more the directions to the flat, given by the landlord, should be more precisely. The house number is not that recognizable and the stairs to the 2. Floor are dark, dirty and narrow.(There is no elevator, so keep in mind that you have to drag your luggage up there).
Also the district, Kowloon City, although it definitely has its own charme, the people here are obviously not used to foreigners, and unfortunately I experienced some hostility.
For foreigners, Hong Kong Island is a better place to stay. Also to save some money and time you spent on public transportation to get to Hong Kong Island. For MTR and Bus Station you have to walk 10-15min (when you hurry up).
So in conclusion, it was far away from horrible, but also far away from "the best time of my life". It was okay.
Thank you!