I have 5 close friends that also play warhammer 40k. We play a lot of games together. I play tau, with the others playing necrons, orks, tyranids ultra marines and a black tempar grey knight mix.
Our games are sometimes 1v1, 1v1v1, 1v1v1v1, 2v1, 2v2, 2v2v2, 3v3, and sometimes all 6 of us play on the same map against the other 5 players. (We know that sometimes means not using correct deplyment zones but its just for fun, we follow all the other rules correctly. And he When we have deployment next to each other in the case of 1v1v1v1 or all 6 playing we made a rule saying that you cannot enter another players deplyment zone until your turn 2.) When we play with 3 deployment zones we use a triangle map that we created ourselves or we use the deplyment on each end of the map with a deployment circle in the centre. We play mostly kill points and tactical objectives games with matched points limits, except for the 2v1 game when we play that the single players points matches the points of the 2 players combined for fairness. Again i know this isnt alway correct but its just for fun in these games, although we are all very competitive amongst ourselves.
This means most games I play are against different armys and therefore i use a wide range of different troops in a single game, and the good thing about this is that you cannot possibly tailor your army against a single opponant.
The main point of this topic is the ATS. I find it very valuable when playing against the ultra marine, black templar/grey knights and necron players. without using math hammer i find that without ATS my army is a bit lack luster against there good saves. I use it on stealth suits ghost keels missile sides crisis suits and commanders(except QFCobviously). Specifically when using missile pods and cyclic ion blasters making it -2 to AP in my opinion works far better than just -1 and again without using math hammer believe -2 is approx 30% better than -1, because it almost doesnt matter the amount of shots you get if you cant get past there armour. This is even more evident when you factor in cover, I don't want to spend 160 odd points on a cyclic ion commander to only kill a few marines in cover, i cant justify it.
In the case of stealth suits i alway put the ATS on the bust cannons and multi tracker on the fusion blaster, in my mind we alreay have enough S5 AP0 weapons from FWs ang gun drones.
I read an article recently saying 8th edition is the age of mobility, AP, and multi damage, and i agree with this whole heartedly. But i find most people saying that they would rather (specifically for crisis and commanders) the extra gun that the ATS, which is true in some cases but in others it baffles me.
Im just looking for your experience with either using ATS or not and would like your opinions on the matter. Thanks again.