I would refer those who are interested in the recurring propulsion problems, which are IMHO, very relevant, to a thread giving the real story. Rather than go into the lengthy history of the more than twenty times this same problem has cropped up on M-class ships; the thread is near the bottom of page 11 and can be found by doing a search on "discussion of propulsion failures".
This problem is only minor if you are one of the lucky passengers on the Millennium, Infinity or Summit who has not yet encountered this problem.
After reading the comment about a "minor problem", a dear friend of mine reminded me about the cruise she was on in Alaska on the Infinity when this ship was having one of these propulsion failures and the ship arrived five or six hours late. After waiting all that time on the pier, by the time boarding was completed customs had closed. So instead of sailing the ship sat in port over night and then the next morning all passengers were forced to disembark and go through the whole boarding process all over again. Net result was almost two days were lost from a 1 week cruise.
Now I doubt if this would be called a "minor" problem for those onboard!!!!
For me, I would not call a car that worked, most of the time, or an airplane that had no engine problems, most of the time, premium and I feel the same way about ships.