The reason for bringing the T-Drone is its weapon, a Smart Missile Launcher. This can be fired directly, or used as a Guided weapon against enemies that have been put into the Target state by Forward Observers or the Spotlight hacking program. When making a guided shot you will ignore the usual -6 modifier for a Speculative Fire and gain a +3 bonus for Guided meaning that you will almost always be shooting at BS 18. Since it is only burst 1 you usually do not want to fire it in a F2F roll, but with Assisted Fire and BS 12 it can be a surprisingly good shot.
In melee it's poor CC stat means it will almost always be better to use Electric Pulse and hope for a poor roll from the opponent (a 35% chance) than to try and fight it out.
Drones are almost always better shooting than Dodging, if they have the option, because of the usual -3 penalty on Dodges and Change Facings that REM troopers suffer. A drone's Silhouette is vertically smaller than a standard trooper making it easier for them to take some kinds of cover, which they will need as they cannot go prone.
Because it has Structure instead of Wounds this unit possesses a second Unconscious state. In effect, it takes one more wound than normal to remove them from the table. It also ignores the "straight to dead" effect of Viral and Shock ammunition.
G: Remote Presence grants Courage meaning it can always choose to not take a Guts roll.
Placing the Supportware Enhanced Reaction or Overclock can make the T-Drone deadly in ARO with B2 missiles at approaching enemies. With Assisted Fire it can ignore cover and add Shock to its AP+DA ammo. This does effect Guided shots as well, meaning you can rain hell on enemy troopers and be certain they wont get up again.
The T-Drone is very vulnerable from short range. Try and attack it with superior modifiers and force it to dodge rather than shoot. It is best to attack with single units, rather than risk a member of a fireteam being too close to the active model and getting caught in a blast.
T-Drones work best with multiple FO models to support them. Hackers CAN target enemy models, but it is order intensive and not usual the best plan. This drone also can work well with a M-Drone that can forward observe or Sat Lock enemy models for Guided Fire.
Keep it hidden. The T-drone is going to earn it's points by Guided fire, so by all means put it way back, or even inside a building so long as there is an open window or door. Guided only requires that you have ANY exit to a room available for the attacker and target so there are lots of good places to hide on a typical board.
Active Turn Role
The T-Drone will be hoping someone sets it up for Guided Fire. Other than this is should probably hang back and contribute it's order to the order pool.
Because of it's penalties for Dodging shooting is often the best option for a T-Drone and also a good deterrent for enemy troopers. Remember that if Overclocked it will get to fire at B2 in ARO which will give some opponents pause.