I did some comparisons in the training hall, and my data show that Unique Variants increase by 5% for each level up they go. So, for example, medium damage vs. gremlins, means that your weapons will do 10% more damage against gremlins. I theorize that a high attack speed increase will increase the speed of your weapon by 15%. Since I can't find exact figures on wiki or this anywhere else, does anyone else have knowledge of how much unique variants increase the gears effectiveness?