My friend and I did this tour the first day and it was a great introduction not only to the food, but also the culture of Vietnam. As others have noted, Ha is an excellent guide, something I realized even more after spending a month in Vietnam and having some downright terrible guides. He really cared that we understood everything he said and that we had a comprehensive experience.
We also appreciated the fact that he spent about double the listed time of the tour with us and even took us down an almost claustrophobic alley to show us how people live in the Old Quarter. If you're staying in the Old Quarter, you must consider this tour!