I have been working as a chef for over forty years. We have a professional sharpening service that comes into our work place (at the request of the owner) and who does all the house knives and everyone's personal knives... except mine. I have seen his work and I wouldn't let him anywhere near my knives...but that is just my take on his work.
I have lots of similar services over the years and the view expressed above seems to be my take on the vast majority of those services.
When I was in culinary school and took the class in Chinese cuisine, we took a walking tour through San Francisco Chinatown with the instructor who was a well known chef and author. He pointed to a restaurant that was full of Asians and said that must be a sign that the cuisine is good there. Then he laughed and said not necessarily so. Just because it is crowded and people are paying money to eat there it doesn't mean it is good. Asians people are no better judge of quality than other people. Make your own judgements. He then pointed another restaurant that was sparsely populated and said it had much better cuisine, but ...make your own judgement. That has stuck with me through the years.