Dr. Tong was my dentist even when he worked for someone else, and I tracked him down after he opened his own office. He has done somewhat extensive dental work for both me and my wife, as near as I can tell that work was successful. He made appropriate referrals for a couple of pieces of work that called for specialists. Dr. Tong is very low-key and reassuring, good for the nervous, and his office has an unusually high level of attention to the amenities.
He is also thorough about the dental care he provides. I suspect this had something to do with motivating him to open his own practice. His office seems state of the art; I have certainly been treated in dental offices that were much less well-equipped, not to mention less spic-and-span.
In my opinion it is a plus that he is continually pursuing advanced training and certification in general dentistry--not everyone seems to care enough to intensively advance their knowledge and abilities, and in my experience providers who pursue independent certifications that require significant additional coursework and passing a stiff national exam are serious about this. I like to see that.
In short, he and his office employees seem to do good work and seem to care about it.