I am very fond of Greenlee tools. This type of hole saw cuts a very clean, centered hole. It has a shoulder to prevent the saw from going too deep into the surface of the material being cut. This is especially good when cutting into a hot electrical panel.
This is a quick change set. It allows one to switch saw sizes quickly without unthreading the saw from the mandrel to change to a different size saw.
I've been wanting to buy one of these sets for years. I will enjoy this set for many years.