Just as it says, it's a game about butlers made by developers who love butlers. It's cliche in these kinds of games for servant-master relationships to turn into a relationship between equals, changing the concept drastically. When that happens in this game, it's a Bad Ending, and in the True Endings there is no such thing. Quite refreshing!
The protagonist, Tomoaki, may have a rough start as he gets used to the novel idea of having six butlers at his beck and call, but that's due to suspicion about the circumstances that made him their Master, and it's not entirely unjustified. Soon enough, he gets to know what it is to be a master in both body and soul, and his butlers are pushed to the limits of their own endurance.
While all routes are made to be enjoyed equally, their different tastes mean that you may have preferences. Whether domination of the strong, humiliation of the proper, corruption of the damaged, exhilarating the stoic, or simply bringing the strong willed to heel, there is much to enjoy within those hallowed halls.
If you think it is too difficult to choose only one butler, know that the game gives you the option to enjoy the attention of more than one at a time.
If I have any criticism to give to this masterpiece, it is simply that there are not enough alternate sprites with marks even when the butler's appearance should have changed. Sad, but understandable.