In 3.8 it is now trivial to sustain T15-16 maps. I used to always give my best rolled T16 maps to Zana, but she doesn't add anything to the main map itself. The map she offers is better if the main map is higher item quantity, but not substantially so. I am not a big delver at the moment, so I don't really use Niko. That leaves me with Einhar, Jun and Alva. All three add brand new encounters to the map. I have been getting good red beasts to sell so I have been sticking with Einhar with Harbringer mod, who is your favorite?