I was in Manila earlier this year, for the fourth time. It's a rough city (and I get a kick out of cities). Much of my walk through Malate/near Rizal Park (a "tourist spot") was riddled with choking pollution, or avoiding syringes and glass. Street food in general consists of garlic, garlic and peanuts, intestines, halo halo (a polychromatic saccharine dessert served in a flimsy plastic cup or bag), and balut. Look that last one up. There are wealthier areas such as Makati, but those are just nicer hotels and malls, so by that point, why did one even bother traveling to Manila?

As for HCMC, haven't been in thirteen years, but I remember three things: good food, getting harassed by rickshaw drivers with joss sticks, and crossing streets was a major pain (the sheer quantity of motorbikes is why).