Nice. I was there back in 1998 which was just 6 months after the communist North of Vietnam opened up to western (non communist) tourists. I imagine it has changed quite a bit since then. At the time most of the tourists were Chinese business men who would cross the boarder for 'pleasure' trips.
We didn't see loads of westerners but there were enough I guess, certainly Ha Long bay had a lot but Hanoi not so many. We enjoyed it though, and will definitely go back.