Robusta and Arabica are coffee species. Culi is a name for peaberry beans, which are classified by shape, while Moka is associated with Arabica coffee.
First decide whether you need green coffee for roasting or a finished roasted product. For green coffee, compare the offered lot, processing and green-bean specification. For roasted coffee, compare the species or blend, roast and intended preparation, then
taste the samples under the same conditions.