Vietnamese coffee is overwhelmingly of the robusta variety and therefore can't be any good. Never had Cao Nguyen, but I used to drink Trung Nguyen every now and then. I believe all of the Trung Nguyen line is robusta unless they specifically say arabica bean. Here in Texas, most of the Vietnamese cafes use Cafe Du Monde with chicory for their iced coffee drinks. It's easy to get and I guess it does the job if you're going to add lots of ice and sweetened condensed milk anyway.