Who would you prefer to welcome as Robot Overlord? Data or Kryten?Kryten.
His guilt program keeps him in line far more than Data‘s ethical subroutine. At worst, Kryten’s jealousy has prompted him to use a tank to disrupt the Dwarfers good time in order to force them to eat his lobster dinner. He is being a jackass there, but that is a character flaws one can tolerate because of his good qualities, like empathy and self-sacrifice.
Data is cold and often clueless about dealing with humans. He has butted heads with those under him the couple of times he has taken command because his lack of emotion makes him seem too distant to be an effective leader. His malfunctions have had disastrous results, too. When not in control of himself, he has taken over the ship, nearly allowing a sick child to die in the process of diverting it to a new location, has inadvertently injured people because he does not know his own strength, threatened to kill hostages, plotted a coup with lore, and went on a rampage on Bak'u. That does not count the issues caused by his lack of understanding of human custom when he has been in control of his actions, and some of the more questionable decisions he has made, such as attempting to kill Armus and Fajo in cold blooded revenge for their actions.
When it comes down to it, kryten has better people skills and easier to deal with malfunctions.