So why breachers?

[Tomadai]

I've been looking at the ad mech army lists to get a good idea on building my own, and I've noticed that on the cult side of things people favor the breachers over the destroyers. and from my thought process all they are good for is either breaking tanks and fortifications, but isn't that  or just being a general meatshield for the Dominus. Destroyers seem better equipped for general eradication purposes if the need for firepower.

[Vel'Cona]

Really?  This hasn't been my experience at all.  I think some folks may like the reduced points costs and better armour save of Breachers, but in most builds I've seen it's Destroyers with Heavy Grav Cannons.  That being said, Breachers aren't a bad choice since they can spam Haywire to kill armour or Torsion Cannons for MCs, and the Holy Recquisitioners Formation offers mobility (of a sort) to AdMech (and Cawl in particular).  This may be why they're seeing a temporary resurgence, though again some of that could just be players that subjectively prefer the look and "purpose" of Breachers.  :)

[Magos Takatus]

As far as I've heard from the forums and the Youtube battle reports the go-to weapon has generally been the Heavy Grav Cannon. I have seen a few people mixing in Arc Breachers but the Plasma Culverin and Torsion Cannon have languished until the arrival of the Haemotrope Reactor and the Fall of Cadia book respectively.

 

I don't have any hard data myself since I've not played a game with my force yet.

[Tyriks]

I agree with Vel'Cona and Flame Boy.  In store I only see breachers used (outside of my own lists) in Holy Requisitioner formation, and often I only use them to avoid grav spam since I don't find it all that fun to play in casual games.  I think grav access is a big part of why you don't see breachers more - it doesn't cost them very much and grav is just the best weapon the Imperium has right now.  The plasma cannons are decent, especially in a War Convocation when they can't get hot.  Between plasma and grav the destroyers can somewhat reliably take down any enemy in the game (except flyers, but join a Dominos with memento-mortispex to gravaphrons and that flyer will crash and burn post haste).  

 

The breachers, by comparison, are pretty underwhelming.  Yes, haywire can more reliably ruin super heavies, Land Raiders and the like, but there aren't usually very many of those in a game, and it struggles against a lot of targets.  The torsion cannon is pretty unreliable - I've fielded it a number of times against Eldar and Tau, hoping to bring down some MCs, but one shot each just ruins them.  Any cover, or a bad roll on that bs3 and your shot is wasted.  Grav is, in my experience, always going to perform better against MCs because you aren't putting all your hopes in that one shot.  So the breachers are just not any where near as versatile as the destroyers.  

[MagicHat]

The first slot will in general always be Heavy Grav Cannon destroyers, but I like Arc Breachers in the second. 

[DeStinyFiSh]

I agree with Vel'Cona and Flame Boy.  In store I only see breachers used (outside of my own lists) in Holy Requisitioner formation, and often I only use them to avoid grav spam since I don't find it all that fun to play in casual games.  I think grav access is a big part of why you don't see breachers more - it doesn't cost them very much and grav is just the best weapon the Imperium has right now.  The plasma cannons are decent, especially in a War Convocation when they can't get hot.  Between plasma and grav the destroyers can somewhat reliably take down any enemy in the game (except flyers, but join a Dominos with memento-mortispex to gravaphrons and that flyer will crash and burn post haste).  

 

The breachers, by comparison, are pretty underwhelming.  Yes, haywire can more reliably ruin super heavies, Land Raiders and the like, but there aren't usually very many of those in a game, and it struggles against a lot of targets.  The torsion cannon is pretty unreliable - I've fielded it a number of times against Eldar and Tau, hoping to bring down some MCs, but one shot each just ruins them.  Any cover, or a bad roll on that bs3 and your shot is wasted.  Grav is, in my experience, always going to perform better against MCs because you aren't putting all your hopes in that one shot.  So the breachers are just not any where near as versatile as the destroyers.  

 

This...

 

I love the Breachers, the long Haywire range is amazing, but by far not as good as 6 Grav shots per Serv !

[MajorNese]

If I include servitors, mostly the breachers are the first ones. Grav is nice against riptides and such, but a 42" threat range on vehicles is a huge deterrent for anything with an AV. That said, grav just doesn't work well enough against superheavies (need 6s for a lost HP), and need a dominus or Carl to make up for their crappy armour. Breachers are more likely to act on their own and not get shot to pieces by any heavy bolter, so a squad or two will do the long-range AT to let my vanguard engage anything with toughness instead.

[thevoodooman]

Cawl's mega formation with the holy requisitioner is probably why they've reappeared.  The haywire cannons are useful enough

[Tomadai]

It does seem that Cawl is a big reason that Breachers are becoming more popular, And usually in a Holy Requisitioner Formation. Other than that you're just taking them for anti-tank, which isn't really an issue in a pure admech force.

[DanPesci]

The first slot will in general always be Heavy Grav Cannon destroyers, but I like Arc Breachers in the second. 

 

This is how i run them.

 

being able to apply haywire over a potential 42" range is awesome, they'll reliably put HP onto heavy tanks, knights, and pop transports so that my vanguard can irradiate the meaty contents.