It was our 1st visit to Vietnam and I loved it, so colourful and vibrant, and very interesting.
We stayed in Phan Ngam Lau area which is really the backpacker district , it was great we were surrounded by lots of cafes, bars, internet cafes, shop and restaurants.
We had heard Vietnam was expensive but I found it to be cheap, i.e we had a really good Thai meal for two with a couple of beers for $11 , the trips were very cheap like the mekong delta $9 for a full day !!!!!!!!! extremely good value .
Saigon struck me as being quite clean , we spent a lot of time walking around the city and it was delightful , when we got tired we used the motorbike taxis and cyclos , I would recommend Saigon as a great destination and enjoyed every minute.

will report a little on Phnom Penh later as I am a bit jet lagged