The concierge at our hotel (the exceptional Hanoi Elegance Emerald) recommended us a topline cruiser for the Halong Bay overnight trip. The Calypso Cruiser was supposedly the best of the lot and many guests had enjoyed a stay there. Although the weather was cold and skies winter bleak, the junk was lovely and comfortable. The rocking motion didn't induce any form of nausea. At night looking out across the bay you can see other boats anchoring.
The staff assisted us in a small cooking class to make cha gio (spring rolls) which added a little fun. Otherwise dinner included a mix of prawn cocktail, salad, clams, spring rolls presented electrifyingly on a pineapple, not very good fries (for some Western familiarity), chicken, fish and fruit.
None of the food was outstanding but it was satisfying enough. It is a boat after all.
After returning from the trip, I commented to the concierge that the stay was nice, however there were some cockroaches in the rooms (not mine but others) and that other guests had managed to get a discounted fare of about USD20 less from a travel agent. The concierge took this on board - later that day the manager of the junk company came to the hotel in person. He greeted me and apologised for the cockroach issue. I was reimbursed the difference in the discount fare and offered a free hotel transfer at the expense of the junk company.
This service is impeccable. I think given that you can't completely immune any cruise from the issues I noted, I can't recommend the hotel or junk enough.