Also sailed on the Westerdam on Jan. 4. There was a stomach virus outbreak but I think some of the reviewers responses are a bit over the top. We had a great cruise, and, importantly, DID NOT get sick. HAL took aggressive measures to halt the spread of the virus, and, now reading about outbreaks on Royal Caribbean, Norwegian, and Princess, maybe they knew what they were doing. (Although in some respects HAL might have been excessive. Why was it ok to keep the shops and casino open, but not the library?)
We had a couple of small problems with our cabin which the staff addressed and followed up with a phone call to make sure we were satisfied. The food was very good. The preventive measures did slow service in the buffet (no self service) and dining room (no rolls left on the table, eg). But we saw these as minor.
On our cruise, while the hot tubs were closed, the outdoor pool was open and being used.