Handsome factory in Causeway Bay was pretty good for hair and beard trim. Been using Selvedge on Pottinger for past several months which is a step above however the person that normally cuts my hair has left so just waiting to hear where they go.
I've changed the products I use in my hair now as a result of the cut I get and they smell pretty good, too!
Hair House in Central (off LKF) have a sink against the window in the back corner and wash everyone's hair before cutting. Never been to the other location. Handsome Factory have a sink but it is small and not set up to lean back and have your hair washed. I suppose it is probably possible to wash your hair there but it wouldn't be comfortable.
At other places I'd get a nice hair wash but an average cut, whereas at Handsome Factory it's a wash if necessary (I don't use too much product or heavy, greasy ones) and an ace chop ¯\_(ツ)_/¯