My wife chose the operator based on reviews and we were happy with our experience. Essentially it’s a macro cruise that covers all logistics required to see the bay. Pick up meals, guides and return. Our guide Duke was very well organized and fourth coming about expectations, left no stone unturned. The staff and facilities were pleasant, meals were generous. The boat itself the Stellar had about 20 cabins but still felt intimate. The UNESCO site itself is mobbed and trampled by tourism, which is inescapable but unfortunate. Glad we went, would suggest the tour to anyone visiting the Hanoi as an overnight trip.