You can drink it of course. It' just that 90% of Vietnamese coffee is Robusta. I'm not an Arabica snob, mixing in a little Robusta is always good, but to drink only Robusta is not my thing. Nor is adding condensed milk to cofee, a real nono .
There are a few good Vietnamese coffees, but on the whole Indonesia and Thailand have better coffee I think.
Food is really good though.