It is not unfair, and there is a comparison with A sorted vector as well. And the author correctly indicated the reason as of why the sorted vector is performing better than the unsorted vector. The cache friendliness is key. And it shows that for small sizes of elements an array or vector would perform better. It simply depends on your needs.

I would be interested in comparing an stack based array with integers to the sets as well.

The article includes binary search of sorted vectors.