We stayed at Vien Dong for 3 nights in November 2012. As we had not booked ahead, we stayed the first night in a room overlooking the side street and asked to be moved to a room overlooking the harbour for the next two nights where there was a balcony and a great view. We paid $10 per night (this was off season). Although the rooms are very simple, they are very clean and have air con + fan. The bathroom is essentially a wet room and again very clean. There is also a lift (nice to have given the hotel has 6 floors).
Most of all, Mr Truong at the front desk was very helpful. He provided us with useful local information but never appeared to be pushy. Like the previous reviewer we did not eat at the hotel or bought tours through it so we can't comment on that.
We can only echo the other good reviews about this hotel by saying it was a nice stay in a very affordable and simple hotel fronted by a very pleasant and helpful hotel manager.