We have been there off season and enjoyed it. But don't go to Cat Ba during summer weekends and national holidays unless you love Asian crowds.
We are a family with 4 children, so we enjoyed the clean and spacious rooms with two queen size beds. Furniture is cheap - even the hotel is less than one year old, it shows already signs of wear and tear. Breakfast is ok if you avoid the pancakes.
The manager was very friendly. When the TV in our room didn't work and could not be fixed, he offered us to move to another room.
We paid 25 USD per night - good value.