My primary place to go to Vietnamese food on the east side.
Ha Long Bay provides broader selections than Saigon Noodles and Pho Nam on the west side, as it has many entree dishes, while other places specialize in noodles and rice dishes. For the Vietnamese entree, ginger chicken is one of my favorite. Personally, I almost always stick to the entrees in Ha Long Bay and go to Saigon noodle for their lovely pho.
Beyond its VT offerings, Ha Long Bay has a big menu that also blends in Thai and Laotian dishes. Thai curry plates are as good as any other Thai restaurant in Madison.
It always gets busy in dinner time. Make reservation if you can.
Overall, the quality of food is very good, and consistent. A very well-rounded restaurant. Service has been satisfying. The only minor quibble is that the menu is so large, and many items are in its original languages. While I truly appreciate the authenticity associated with it, it could difficult for the first-timers to order, and even more difficult to remember what I just ate.
I highly recommend Ha Long Bay.