The Tau Empire Advanced Targeting System

I have literally never seen anyone use this device except for me but it is a fantastic upgrade.

For those not aware, 7th Edition eliminated the Precision shot ability from Independent Characters and so outside of Sniper Rifles, there aren't many places you see Precision Shots.  The Imperial Guard have an Order they can give units to grant it and it's a very good ability for their units when they"blob" up but really it's a much more uncommon mechanic now.

The fact that Sniper Rifles lost Pinning in 7th edition has made them less attractive, making Precise Shots even less common.

The Advanced Targeting System gives the model Precision Shot and gives Characters with it a 5+ Precisions shot.  This is an absolutely fantastic upgrade if you are able to attach it to a bullet hose.  The Tau Empire have two.

The Crisis Teams can come equipped with two Burst Cannons, for a total of 24 STR 5 shots per full unit.  That's impressive, especially when hitting on 2's which means even if the targeted model doesn’t die to the wound itself, that many shots is going to rapidly remove his ablative wounds anyways!  If you are the Shas'Vre in the unit, you get 8 chances on 5+ to lay those wounds on the enemy models you want to.  This allows you to "pop" the Power Fist wielding the Death Company members or whack the incredibly dangerous Power Axe wielding Sergeants that make the Imperial Guard blobs so dangerous.  Look out Sir Rolls will obviously blunt some of it but you are talking about a mere 2 point upgrade! 

All enemy units have what I call fangs:  members who allow the unit to push over the hump and that, without those members, the unit becomes considerably more mundane.  Giving a Crisis Teams a way to pull those fangs is pretty impactful over the course of that enemy units life.  Also when someone throws a 2+ armor save "tank" out front, you can ignore him several times with this!

The Stealthsuits could conceivably be a better choice in some ways to use the Advanced Targeting System.  They also get 24 shots and have a character, though their character gets less chances at the 5+ Precision Shots.  The unit walks around with 6 wounds like the Crisis Team, BUT instant Kill wounds don't take away their firepower as quickly.  Stealthsuits have a 4+ Cover save in the open, which is amazing on its own, but add to that their ability to walk to the enemy door step with Infiltration round 1 and start pulling fangs from the get go and bouncing back?  When they are in cover they are 2+ cover saves, which they can sometimes jump back to.  If you wish to give the enemy heart burn and force them to move laterally instead of forwards as a part of your strategy, the Stealthsuits with this ability could be a very compelling reason to take the Advanced Targeting System.

One last point.  Although I can easily agree that there are more important things you need to place on Broadside Battlesuits than this upgrade, imagine sniping characters with that STR 8/AP 1 Broadside cannon.  It's fun to think about, even though it would probably be a bad idea.

In any event, as a Tau opponent, it might not be much fun to get hit with 24 or lord forbid 72 such deadly accurate shots from three such units.  An infantry army would find this getting old fast.