Remember that Seinfeld episode where they talk about a restaurant that has every sort of international cuisine? Sometimes it seems like Ha Long Bay is trying to be that for Asian food. The menu is absurdly long, and has Thai, Vietnamese and Laotian Food. Ordering can be a little overwhelming.
In my experience, they don't do Thai food as well as the dedicated Thai restaurants in town, and same with Laotian, but every dish is a very solid attempt, and the portions are huge. If you want Pad Thai and your friend wants Pho, this is the place. I would generally say that seafood is not the best bet here. It must be coming out of a bag frozen -- the mussels were particularly tough and fishy.
There are a ton of Vietnamese specialties that I've never had, and we are having a good time working our way around the huge menu. I dubbed V6 today "general Tso's Eggplant." Yum.
The staff is friendly, and refills on rice are free. I've had very slow service when it's been busy sometimes.