Because all of these look so good, I'm voting based largely on the reasonings given for the design in addition to what, in my opinion, is the most important uniform element--a clearly visible distinction between the 3 tracks.
On the battlefield, being able to tell at a glance who can patch up your wounds and who would be better patching up a turret can mean the difference between a glorious victory and a swift entrance into Sto-vo-kor.
Thus, my choices are: H, F, and C
(also congrats to H for managing to use the same system as DISCO without letting Tactical and Engineering be so indistinguishable that I physically can't tell them apart)