It is my understanding that completing the KA for the first time will grant one the assimilated accolade as well as a Liberated borg bridge officer (of the science variety). I was wondering if the terradome stf grants any bonus rewards as well?
Technically, the borg BO is not a reward from the mission. Rather, it is an accolade that you get from running into one of the assimilator machines (I forget what they are called) during the ground portion of the mission. Once you do that, you get the accolade and don't necessarily have to finish the rest of the mission to get your BO. (But at that point, you might as well finish because you are near the end of it anyway.)
No special reward that I know of for doing Terradome, other than the usual random purple drop.