I have tried a few pure robusta coffees and I always find them lacking. They all have that initial kick, which I may like (or not, some coffee is just terrible), but after that, nothing. All flavors are gone, the rest is like water with some chemical bittering agent added, which I find particularly frustrating.

That's why I always drink my robusta as a blend, Italian style. I still get the initial kick of Robusta and its characteristic bitterness but Arabica is still there to fill in the gaps.

But I admit I didn't try that many pure Robustas, maybe some don't suffer that problem.