Reviews from even one year ago are pretty much useless for predicting what a future cruise will be like. And it is also a fact that reviews tend to be posted by people from the two ends of the spectrum - either they loved the cruise so much they can't wait to share their enthusiasm, or those with an axe to grind because their entire cruise was ruined because they didn't like the iced tea. Balanced reviews are less often posted.
For a historical perspective, in the 16 years since Ryndam first came into service it's lowest CDC sanitation score was 89 (and that was in 1995) and it's highest score was a 99 last summer. It was inspected on 6/17/10 and received a 98. 100 is exceedingly hard to attain. 85 is passing. Thus I feel safe in saying it is a clean ship.
Norovirus can be hard to remove from a ship, and thus it is common to see the same ship struggling with it for more than one week in a row.
It is also important to note that norovirus has nothing to do with the cleanliness standards of a ship or it's crew, or their handling of food. The virus it most likely introduced by a passenger who boards the ship knowingly ill, or someone who doesn't know it yet, but once aboard they spread the virus by touching surfaces, utensils, etc.
Older ships tend to have occasional sewer-like odors on lower decks. It's just something that comes with aging piping, drains, tanks, etc. I've never been overwhelmed by it.
Don't worry about this stuff. Just make sure you wash your hands frequently with soap and water and don't rely on hand sanitizers. Alcohol-based hand sanitizers don't kill viruses. Those with Benzethonium Chloride and Benzalkonium Chloride do.