Heavy on Drones? (rolls down window) RUMMY! SOMEBODY WANTS TO TALK TO YOU!
GrimSqueaker will be along shortly to congratulate you on aiming for drones. I think that's a generally poor plan, myself. Here's why:
Drones are more expensive than Firewarriors, but have comparable firepower (and less range). They don't have a transport option, aren't sufficiently durable to survive, and aren't really any better in assault than Firewarriors. They also compete in the Fast Attack slot against more useful Pathfinders, vastly superior Piranha, and the Flyers.
Gun Drones are *great* when you get them for free attached to a Devilfish and Piranha. Paying to field them? No thanks.
I guess I can maybe see a reason to take Gun Drones on a Coldstar suit (adds to his firepower), but it also opens him up to taking Morale tests if he loses any of them, and having your flying commander run away because his favorite gun frisbee is blown up kinda sucks.
Although I do have a honest question about the Tau though. Which is morally better, regular Tau or the Farsight Enclaves? Especially when it comes to the Greater Good?
This will vary depending on which fluff you choose to emphasize and how you want to play. I don't think it's definitive. Certainly Farsight is more populist and egalitarian, letting all castes interact and work together, etc.. He's also a bloodthirsty lunatic, who may or may not have his mind controlled by the Old Ones, so there's that.
The Tau Empire itself is cold and dystopian in a few ways (controlled breeding, mind control, etc.), but it's also significantly more peaceful, diplomatic, and prosperous.
Pick your poison, basically.