I've seen him and found him very good with my then 14 month old. I'd recommend him. I've read some good reviews about him on here and other sites but have not read anything bad.
My daughter did need to have grommets placed due to fluid in the middle ear, but she had the surgery done at QMH so Dr Hui didn't do the surgery. He used to be at QMH before he went private and is highly respected there (they recommended him to me) - also he worked well with the public hospital too.
Definitely one of the better doctors (of many!) that I've seen here in HK.