Eat a Box of CoCs

Starting right at the beginning, like a noob. I've managed to play a few Battlebox games with Convergence and thought I should write my thoughts on the matter, to tag along with some pictures of my CoC :O

Bright red CoC, ready to party

Overview

I think the CoC Battlebox is actually quite strong and well put together compared to some of the others (1). It has a good single target damage output thanks to the Cipher and the Synergy spell, it has good survivability thanks to Syntherion's toolkit and Field Marshall bonus, and has good control options with the Cipher and Mitigator's guns. It does suffer a bit in that it lacks ranged damage output, and the two lights hit like wet noodles compared to other Battleboxes so if you lose the Cipher, your CoC is deep in a hole.

Syntherion

The first thing to point out about Syntherion is that he quite respectable defensive capabilities in the Battlebox, largely because he is able to camp quite a bit of focus thanks to Induction and is Repairable (by the Galvanizer and his Field Marshall). This makes him quite hard to kill. He also is pretty good in melee, with 2xP+S 14s thingos to swing with (which can get pretty threatening with Synergy).

His abilities are also quite sweet - Resourceful allows him to upkeep for free (even more focus efficiency to allow him to camp more focus) and Field Marshall: Auto Repair, which makes a huge difference in a format where things are not usually one-rounded.

His feat Technological Superiority - average at the best of times - is certainly not stellar in the Battlebox. It is used primarily for free charges but that extra pseudo focus can make all the difference to your charging Cipher as it is effectively an extra attack. The Weapon Platform effect is situationally useful. The main thing to remember is that although you can shoot while engaged, if you shoot something that is engaged, you get a -4 to hit. I find the best use of it is to get extra range on a KD/Flare shot via the Mitigator/Cipher, or to throw out a Crater shot on a potential counter-charging warjack. It is also pretty much a guaranteed +2 to hit for your Cipher when he throws it on his charge target and it deviates 0".

Horrible sculpt/model, but I think the red baboon face gives him some personality.

Moving onto spells, he has 3 shining stars:

• Reconstruct is amazing in a Battlebox game when put on your Cipher. This is because a lot of Battlebox games basically come down to who loses their heavy first, since it is rare for other models to be able to deal enough damage to take out a healthy heavy. Furthermore, because of the low number of attacks, it is actually quite likely that your opponent will not have enough attacks to finish off the Cipher. Next turn the Cipher auto repairs, you stack Synergy, and get their heavy, then probably manage to win (especially if you can repair the Cipher up some more).
• Synergy is quite good in Battlebox games despite the limited number of models - it is worth the upkeep slot at a mere +1/+1. Even the Galvanizer becomes (somewhat) threatening at MAT 9 P+S 15. 
• Last but not least, Magnetic Hold is a generally nut-stompingly good debuff that simply becomes ok in a Bbox game. The catch is that without arc nodes, Syntherion has to get pretty far up to cast it, and that means you probably want to charge and kill whatever you put it on or risk losing your caster. Thus the -2 SPD and upkeep aspect mean very little. Regardless, +2" of charge threat and -2 DEF is quite good and can win games.

He does have two spells which are more or less 'useless' (aka. 5% spells) in the Battlebox format - Hot Shot and Convection. Convection is basically a shitty 2 cost nuke with no opportunity to grant an extra focus (which with Induction is actually quite valuable) and Hot Shot only really affects Syntherion since the Mitigator only ever does 1pt of damage, and the Cipher has a POW 6 blast AoE that can't really harm anything in a Bbox format outside the squishiest casters.

Cipher

The Cipher is your heavy hitter. It has 2xPOW 18 Penetrator Pistons that stack up very nicely with Synergy. What the Cipher does bring which hard hitters usually don't is buckets of utility, primarily via its phallic face gun.

• The most important shot of the three available in the Battlebox format is the Crater shot. If your opponent lacks pathfinder, this basically takes a model out of the game for a round.
• Secondly, our gun-faced friend can also throw out a POW 6 blast damage AoE. Great for churning up lightly armored high DEF infantry, but in a Battlebox game this is pretty useless unless you're just fishing for boosted damage on a caster when you have focus to waste.
• Finally, Flare is also very helpful if for some reason the target can't be KD first by the Mitigator or in combination with Syntherion's feat as mentioned before.
• Oh, he is also RoF: 2. Neato. Throwing out 2x 4" Craters on Turn 2 can seriously slow down an opponent in a Battlebox match.

Having a gun for a face is certainly logical.
What need does a machine of war have for a face?

Last point - remember that the Cipher is Steady. This means you can do some cool stuff with it, like hitting it with your Mitigator's Bola to unengage it from nearby models so it can walk off and kill something.

Mitigator

This little dude is pretty sweet. I find I get a lot of work out of his gun to KD things. The AoE Puncture does very little in Battlebox games but it is regardless very useful just for the KD. Chewing up your opponent's resources on shaking makes a big difference to your survival in Battlebox games - that's one less attack on your heavy or caster if they get the jump on you!
Furthermore, although he is terrible in melee, you can still use him to build Synergy stacks - even better if you do so via a push or slam. 

I quite like the glowing crotch lamp. Nice touch PP.

The relatively short range of his gun means you have to play him a little further forward than you might like to with a ranged-only jack, but you have so few models in this format that this doesn't matter too much and you can use him to roadblock a bit.

Galvanizer 

Very cute. He doesn't do much, except threaten that he might do something as a result of Synergy stacks. And he can repair everything in your list, which is cool. Grievous Wounds can also be super sweet against Hordes, since taking out an aspect will be quite meaningful. Or taking transfers away. Basically I just use him as a gadfly on the flank, a synergy stack for Syntherion/Cipher, or a friendly little repair bot you can always deal some pain on the counter charge.

Galvanizer's best side.

Conclusion

So the overall generic strategy is to put Reconstruct on the Cipher, Synergy on Syntherion and run everything turn 1 (for 1 focus!). After that, you want to try to kill their heavy-hitter with your Cipher and try to control their models as much as possible with KDs and Crater shots to limit retaliation and give you the opportunity to have good board positioning. Use your lights and terrain to try to control charge lanes, and always keep your eyes on the assassination.

Remember your win conditions - you win when their caster is dead OR all their warjacks are dead. The CoC Battlebox isn't especially great at achieving the former, is decent at achieving the latter, but is quite good at stopping both from happening!

(1) This isn't hard since I think most of the Battleboxes are crappy, especially the Hordes ones.