Hi,
Went there 2 years ago... loved that place for the people. They are usually warm and hospitable. Haven't had any bad enounters with them. I tried the Singh cafe for a day trip to CuChi tunnel in Ho Chih Minh. It's a place not to be missed and the guide was very good.
Personally like Hoi An and Hue better. Hoi An is a small town with loads of tailoring shop and the architectures reminds you of old China. Hue on the other hand is the imperial city of Vietnam in the past. Think it's worthwhile to get a local guide to show u around in Hue if you have some spare cash. You will appreciate the city and its history better. Their english is not fantastic, but you should still be able to understand what they're saying. Hanoi doesn't really leave much of an impression on me. You can catch a water puppet show over there if you feel like getting involved in their traditional art. It's pretty entertaining.
Feel that Ho Chih Minh is not really safe at night, safety is much much better out of that city.
For me, the trip was great, with a combination of nice company, warm vietnamese, and better understanding of the country's history and culture(thanks to the nice guide we got). Hope yours will be as great!
