Hong Kong toilets are clean if you know where to go (and where not too) - as a general rule shopping centres are very clean as there is a designated cleaner there. I find the New Territories are cleaner than HK Island and Kowloon. Small restaurants/cafes will be dirty to westerners but only as bad as some public toilets I have been to in England.
As a rule always carry a spare pack of tissues just in case but not really had to use too much out there but sometimes "free" is taken to the extreme in HK. If you do boat trips, coach trips and other days out make sure you have supplies :-)
Hong Kong toilets are VERY VERY easy to find if you know where to find. Fastfood shops all have toilets and the ones in malls are very easy to find as well. If you think ones in malls are hard to find, then just read the map..plus there are signs everywhere pointing to it. People say public toilets are really dirty, but actually, it's not really. HK really improved their public toilet facilities. There usually a cleaner inside the toilet 24-7 to clean and stuff. They now have automatic taps etc. There is ALWAYS toilet paper in public toilets, ALWAYS. Most tourists say there are none because it's not placed right next to the toilet. Toilet paper is place right at the entrance of the bathroom. It's placed there because some people (mostly elderly) go crazy when they see free toilet paper, and sometimes they take loads and loads to take home. Public toilets are mostly wet because they clean it A LOT. The cleaner mops it all the time!
P.S The toilets at tourist attraction areas are super easy to find and super clean. Same goes for museums
Me and my colleague found the difficulty of looking for toilet in the building. When we try to find toilet, the common thing is go in department store or shopping plaza.
These building are big, large and crowded. But, to find to toilet is difficult. Some building have only few of them in one floor.
Sometime, we have to walk a long way and find the very long queue in front of the toilet.
We also can not find toilet at MTR station.
A huge warning to those who like to use toilet paper - take lots of tissues! ;)
The toilets (well the ones I went in anyway) in Hong Kong don't have toilet paper and are fairly dirty, especially those further away from Kowloon like Mong Kok. You will need to take tissues everywhere you go.
Try to use toilets at McDonalds and similar places, they are a lot better quality - still not the best but better. ;)
Major Inconvenience --> Toliets in Hongkong are terribly HARD to find even in shopping malls!! Sometimes I even haf to sneak into restaurants just to have a leak. This can be VERY distressing at times. Whatmore, the public toliets there are generally wet and dirty! (Major Turn-off) No toliet papers whatever - we solve the situation by carrying a big BOX of tissue (VERY VERY IMPORTANT multipurpose functions) in our haversack wherever we go!
Public toilets are not the best and toilet paper is not usually supplied. Best to carry a supply of tissues or head for hotel bathrooms. In the more upmarket hotels, there is usually an attendant on duty. A small dish is placed on the vanity units for tipping which is pretty much expected. Large department stores also have toilets available.