There are places where the robusta is grown and processed for flavor, not just because it is cheaper or hardier. The robusta seems doomed in the PR battle because it can be more easily abused, but WOW there is a lot of bad arabica around as well. I just bought some prize-winning 100% arabica coffee at Trader Joe's that smelled great through the vent, was recently packed, and it was gawd-awful when brewed (it was private label, not under the Trader Joe label). I tossed the bag out. To get the taste out of my mouth I (ironically) brewed up a cup of my mainstay Culi Robusta, and then my tastebuds quit shivering.
When I introduce these premium robustas to people who have no preconceptions they pick the robusta over the House Blends of well-know expensive brands (I won't name them here because I don't like to put down other coffees and don't like it when people put down my favorites).
My point is that we don't really need to define a "superior" coffee among the several popular cultivated varieties... because this tends to narrow the whole range of flavors down that coffee lovers are "allowed" to experience. Blended coffees, especially from more than one variety, offer taste treats we can can never get from a single source and they will always have an important place in the quest for great coffee experiences.
Try a robusta from a different area if your locals brew robusta for cheap and easy, and maybe you will think a lot differently about it. I lived in Colorado for several years, right down the road from the countries largest and best beef lots, and yet we could not get good steak locally. It was all shipped to the coasts where the restaurants would pay 4X the price. Markets are a funny thing.
Trung Nguyen makes a great robusta and they also carry a Brazilian Robusta but I can't imagine buying a Brazilian robusta from Vietnam, although I did try a sample and it wasn't half bad. But their own trademark Culi Robusta still reigns king I think.