We did a back to back to back Sydney to Yokohama so this review is for the last leg, Hong Kong to Yokohama. The Jewel is now quite old and in need of a refit but provides a good cruising experience with lounges and restaurants to suit all tastes. Our inside cabin was adequate and our cabin steward did his best. Dining was generally good. The two main restaurants were fine, the buffet (Market cafe) often a scrum but the food was good. The speciality restaurants were good. Service was generally good, some outstanding, some poor. Entertainment became a bit samey but we were on the ship for 40 nights so that was to be expected. Ports on this leg of the cruise were great. We did not take any NCL excursions but seldom heard anything good from those who did take them so this is an area on this ship that NCL should look carefully at.
Good inside cabin. Roughly mid-ship to forward so good in poor weather.
Hong Kong is a great port. We did a free walking tour and then took a train to the peak.
Shanghai is very doable on your own. We shared a cab into town then did a free walking tour which was very interesting. Amazing city. Very walkable. Lots to see.
Took the port bus into town and then bought day pass on the city loop bus. Excellent value. Visited the famous falls and a bunch of other sites.
Took metro from Yokohama to Tokyo. Can't comment on Yokohama but Tokyo is incredible city.